Medicare Supplement Plans in Illinois: What They Cover and How to Choose (2025 Guide)

If you are approaching age 65 in Illinois or already on Medicare, you have probably realized that Original Medicare does not cover everything. Deductibles, copays, coinsurance, and other out-of-pocket costs can add up quickly, leaving many Illinois seniors facing unexpected medical bills they were not prepared for.

That is exactly what Medicare Supplement insurance, commonly called Medigap, is designed to solve. Over 750,000 Illinois residents have already enrolled in a Medicare Supplement plan to fill the gaps in their Original Medicare coverage. And with good reason: the right Medigap plan can save you thousands of dollars per year in out-of-pocket healthcare costs.

This guide explains everything Illinois residents need to know about Medicare Supplement plans in 2025 what Original Medicare does and does not cover, how Medigap fills the gaps, which plans are most popular in Illinois, what they cost, and how to choose the right one for your health needs and budget.

At Chime Insurance Group, our licensed agents specialize in helping Illinois seniors navigate Medicare options simply and confidently. We compare plans from multiple carriers at no cost to you. Get your free Medicare consultation, or visit our Medicare Plans page to learn more.

WHAT ORIGINAL MEDICARE COVERS, AND WHAT IT DOES NOT

Before understanding Medicare Supplement plans, you need to understand Original Medicare and where its coverage gaps lie.

Original Medicare has two main parts:

• Medicare Part A: covers inpatient hospital care, skilled nursing facility care, hospice care, and some home health services. Most people do not pay a Part A premium because they or their spouse paid Medicare taxes for at least 10 years while working. However, Part A comes with significant cost-sharing, including a hospital deductible of $1,676 per benefit period in 2026 and coinsurance costs for longer hospital stays.

• Medicare Part B: covers outpatient medical services — doctor visits, preventive care, lab tests, durable medical equipment, and outpatient procedures. Part B has a monthly premium of $185 in 2026 for most beneficiaries, plus a Part B deductible of $257 in 2026, and a 20% coinsurance on most services after the deductible is met.

• Here is the critical gap: Medicare does not cap your out-of-pocket expenses. If you have a serious illness or multiple hospitalizations in a year, your 20% Part B coinsurance alone could result in thousands of dollars in out-of-pocket costs, with no annual limit. Unlike most private insurance plans, Original Medicare has no out-of-pocket maximum.

This is where Medicare Supplement insurance becomes essential. Medigap plans are sold by private insurance companies and are designed to cover these cost-sharing gaps, giving you predictable, capped healthcare costs and peace of mind.

WHAT MEDICARE SUPPLEMENT INSURANCE COVERS IN ILLINOIS

Medicare Supplement plans in Illinois are standardized by the federal government. This means every Plan G from every insurance company covers the same benefits — the only difference between companies is price.

Here is what the most popular plans cover:

• Plan G — The Most Comprehensive Option for New Medicare Enrollees

Plan G is the most popular Medicare Supplement plan in Illinois, held by approximately 45% of Illinois Medigap enrollees. It is also the most comprehensive plan available to Illinois residents who became eligible for Medicare on or after January 1, 2020.

Plan G covers: Medicare Part A coinsurance and hospital costs for up to 365 days after Medicare benefits are used, Medicare Part B coinsurance and copayments, the first three pints of blood, Part A hospice care coinsurance or copayments, skilled nursing facility coinsurance, Medicare Part A deductible, Medicare Part B excess charges — the amount a doctor can charge above Medicare's approved amount, and foreign travel emergency care up to plan limits.

The only gap Plan G does not cover is the Medicare Part B deductible — $257 in 2026. After you pay that deductible each year, Plan G covers virtually everything else Medicare approves.

Cost in Illinois: Plan G premiums for a 65-year-old Illinois resident start at approximately $144 per month from the most competitive carriers, with state averages ranging from $144 to over $200 per month depending on the insurer, your location in Illinois, and your health status.

• Plan F — The Most Comprehensive Plan Available (Limited Eligibility)

Plan F is the only Medigap plan that covers all Medicare cost-sharing gaps, including the Part B deductible — making it the most comprehensive plan available. However, Plan F is only available to Illinois residents who became eligible for Medicare before January 1, 2020. If you turned 65 after that date, you cannot purchase Plan F.

For those who qualify, Plan F premiums in Illinois start at approximately $164 per month from competitive carriers.

• Plan N — A Lower-Premium Option with Some Copays

Plan N is the third most popular Medicare Supplement plan in Illinois, held by approximately 7% of Illinois Medigap enrollees. It covers most of the same benefits as Plan G — including the Part A deductible, foreign travel emergencies, and skilled nursing facility coinsurance — but with two key differences: you pay up to $20 copays for doctor office visits and up to $50 for emergency room visits that do not result in inpatient admission. Plan N also does not cover Part B excess charges.

• Cost in Illinois: Plan N premiums for a 65-year-old start at approximately $101 per month from competitive Illinois carriers — significantly less than Plan G or F.

• Best for: Healthy seniors who do not expect frequent doctor visits and want to reduce their monthly premium in exchange for modest copays.

Other Available Plans

Illinois also offers Medigap Plans A, B, C, D, K, L, and M. Each provides a different level of coverage at different price points. Plan K and Plan L are cost-sharing plans with lower premiums but higher beneficiary cost-sharing responsibilities until an annual out-of-pocket limit is reached. Most Illinois seniors find Plans G, F, or N offer the best combination of coverage and value — but your specific health situation and financial priorities should guide your choice.

High-Deductible Plan G

Plan G is also available in a high-deductible version in Illinois. With High-Deductible Plan G, you pay Medicare-covered costs — coinsurance, copayments, and deductibles — up to $2,950 in 2026 before the plan begins paying. After that threshold, the plan covers everything Plan G covers. The trade-off is a significantly lower monthly premium — an excellent option for healthier seniors who want catastrophic protection at a much lower cost.

ORIGINAL MEDICARE VS. MEDICARE ADVANTAGE, WHICH PATH IS RIGHT FOR YOU?

When you first become eligible for Medicare, you face a fundamental choice: stay with Original Medicare and add a Medigap plan, or enroll in Medicare Advantage (Part C).

• Original Medicare plus Medigap: You keep access to any doctor or hospital in the United States that accepts Medicare — no network restrictions, no referrals required. Your Medigap plan covers your cost-sharing gaps. You add a separate Part D plan for prescription drug coverage. This path gives maximum flexibility and predictability.

• Medicare Advantage (Part C): A private plan that replaces Original Medicare. Often includes prescription drug coverage, dental, vision, and hearing benefits not covered by Original Medicare. Usually has lower monthly premiums than Original Medicare plus Medigap — but comes with provider networks, prior authorization requirements, and potentially higher out-of-pocket costs for complex or frequent care.

Important: You cannot have both a Medigap plan and a Medicare Advantage plan at the same time. This is one of the most common sources of confusion Illinois seniors face when making their Medicare decision. If you enroll in Medicare Advantage and later want to switch to Original Medicare plus Medigap, you may face medical underwriting — meaning insurers can charge you more or deny coverage based on your health history outside of guaranteed-issue windows.

The right choice depends on your health, your preferred doctors, your financial situation, and how much you value flexibility versus lower upfront costs. Chime Insurance Group walks you through both options side by side so you can make an informed decision. Contact us for your free Medicare consultation.

ILLINOIS-SPECIFIC MEDIGAP RULES YOU NEED TO KNOW

Illinois has several consumer protections that go beyond federal Medigap rules — and knowing them can save you significant money:

The Illinois Medigap Open Enrollment Period: Federal rules provide a six-month guaranteed-issue enrollment window when you first become eligible for Medicare Part B at age 65. During this window, insurers must sell you any Medigap plan they offer at standard rates — they cannot reject you or charge you more based on your health history. This is the single most important window for getting Medigap coverage and should not be missed.

Illinois Annual Open Enrollment Period: In 2022, Illinois enacted legislation creating a new annual Medicare Supplement Open Enrollment Period — going beyond federal requirements. This gives Illinois Medicare beneficiaries a limited annual opportunity to switch Medigap plans with guaranteed issue rights. This is a significant consumer protection that most other states do not offer.

Blue Cross Blue Shield of Illinois guaranteed issue: BCBSIL is designated as Illinois's guaranteed-issue Medigap company, meaning they must offer Medigap coverage to any Illinois Medicare beneficiary over 65, regardless of health status, throughout the year at standard rates. For seniors under 65 on Medicare due to disability who did not enroll during their initial window, there is an annual enrollment opportunity from October 15 to December 7, specifically through BCBSIL.

Premium pricing methods matter: Illinois Medigap insurers use different premium pricing methods — community-rated (everyone pays the same regardless of age), issue-age-rated (based on your age when you buy), or attained-age-rated (increases as you get older). Understanding which method your carrier uses is critical to understanding your long-term costs. Age-rated plans may seem cheaper at first, but can become significantly more expensive over time.

HOW MUCH DO MEDICARE SUPPLEMENT PLANS COST IN ILLINOIS?

Illinois Medigap premiums vary significantly based on the plan type, the insurance carrier, your age, your location in Illinois, and your health status outside of guaranteed-issue windows. Here is a clear picture of 2025 and 2026 costs:

At age 65, Illinois residents pay between $47 and $562 per month for Medicare Supplement coverage, depending on the plan and carrier. The most competitive rates for the most popular plans in Illinois are: Plan N starting at approximately $101 per month, Plan G starting at approximately $144 per month, and Plan F starting at approximately $164 per month.

Location matters in Illinois: Premiums differ between the Chicago metropolitan area — including Will County — and other parts of the state. BCBSIL specifically uses different rating areas for Cook, DuPage, Kane, Lake, McHenry, and Will Counties versus the rest of Illinois. If you live in the Frankfort and Will County area, your premiums may differ from downstate Illinois rates.

The price for the same plan letter varies dramatically between carriers: Plan G from one insurer may cost $144 per month while Plan G from another costs $208 per month — for identical coverage. This is why comparing multiple carriers is essential. Chime Insurance Group does this comparison work for you at no cost.

Discounts available: Many Illinois Medigap carriers offer discounts for married couples or household members, non-smokers, annual premium payment, and electronic funds transfer payment. BCBSIL offers a 10% household discount for qualifying members. Always ask your agent about available discounts when comparing plans.

MEDICARE PART D: PRESCRIPTION DRUG COVERAGE IN ILLINOIS

Medicare Supplement plans do not include prescription drug coverage. If you are on Original Medicare with a Medigap plan, you must purchase a separate Medicare Part D prescription drug plan to cover your medications.

In 2025, Illinois insurers will offer 17 stand-alone Medicare Part D plans with premiums starting at $0 per month — though $0 premium plans may come with higher drug costs or formulary restrictions. The right Part D plan depends on your specific medications, your preferred pharmacy, and the plan's formulary.

Important 2025 change: The Medicare Prescription Drug Improvement and Modernization cap means out-of-pocket drug costs are now capped at $2,000 per year for Part D enrollees in 2025 — a significant new protection for Illinois seniors with high medication costs.

At Chime Insurance Group, we help Illinois seniors choose both their Medigap plan and their Part D plan together — ensuring your total Medicare coverage is complete, coordinated, and cost-effective.

MEDICARE SUPPLEMENT COVERAGE FOR ILLINOIS SENIORS WITH CHRONIC CONDITIONS

For Illinois seniors managing chronic conditions, including Parkinson's disease, heart disease, diabetes, COPD, or other ongoing health needs, a comprehensive Medigap plan like Plan G is often the most financially protective option. The predictable cost structure of Medigap eliminates the surprise bills that can arise from frequent specialist visits, hospitalizations, and skilled nursing facility stays.

For families navigating Parkinson's disease or other neurological conditions alongside Medicare planning, our partner Sarah's Haven provides compassionate virtual care, support, and guidance for patients and their caregivers across Illinois and beyond, helping families understand their coverage options and access the care they need.

For Illinois seniors who also need mental health services covered under Medicare, our healthcare partner Hometown NP provides telehealth mental health consultations for adults — a convenient complement to your Medicare coverage for mental and behavioral health needs.

HOW CHIME INSURANCE GROUP HELPS ILLINOIS SENIORS WITH MEDICARE

At Chime Insurance Group, we specialize in helping Illinois seniors navigate their Medicare options simply and confidently. Medicare decisions are some of the most consequential financial choices you will make — and getting it right the first time is critical, especially since switching later can involve medical underwriting.

Here is what a free Medicare consultation with Chime Insurance Group looks like:

We review your current health situation and anticipated healthcare needs, including any chronic conditions, regular medications, preferred doctors and specialists, and expected frequency of medical care.

We explain your coverage options in plain language, such as Original Medicare plus Medigap versus Medicare Advantage, which Medigap plan letters make sense for your situation, and how Part D fits into the picture.

We compare premiums from multiple Illinois Medigap carriers side by side for the same plan letter so you see exactly how much you save by choosing the most competitive carrier for your specific rating area.

We help you understand Illinois-specific rules, including the open enrollment period, the annual enrollment opportunity, and the BCBSIL guaranteed-issue option, so you enroll at the right time with the right protection.

We help you enroll, guiding you through the application process to make sure everything is completed correctly.

There is no cost to you for any of this. Our service is completely free to Illinois Medicare beneficiaries. Get started at chimeinsurancegroup.com or contact our team in Frankfort, Illinois, today.

MEDICARE SUPPLEMENT PLANNING IN FRANKFORT AND WILL COUNTY, ILLINOIS

Chime Insurance Group is based in Frankfort, Illinois, and serves Medicare beneficiaries throughout Will County, Cook County, and the broader Chicago metropolitan area. We understand the specific carriers, networks, and premium structures that serve our area, including the Will County rating area distinctions that affect your Medigap premiums.

Whether you are approaching Medicare eligibility for the first time, reconsidering your current coverage during an annual enrollment window, or helping an aging parent navigate their Medicare options, our team is here to guide you through every step.

We serve seniors in Frankfort, Mokena, New Lenox, Tinley Park, Orland Park, Joliet, Bolingbrook, Romeoville, and throughout the south and southwest Chicago suburbs. Free consultations are available in person, by phone, or virtually — whatever is most convenient for you.

Ready to get started? Visit Chime Insurance Group for your free Medicare consultation.

FREQUENTLY ASKED QUESTIONS: MEDICARE SUPPLEMENT PLANS ILLINOIS

People searching for Medicare supplement plans in Illinois are also asking these questions.

Here are clear, direct answers:

1. What is the difference between Medicare Supplement and Medicare Advantage in Illinois? Medicare Supplement (Medigap) works alongside Original Medicare to cover cost-sharing gaps — giving you access to any Medicare-accepting doctor or hospital nationwide with predictable costs. Medicare Advantage replaces Original Medicare with a private plan that often includes extra benefits but comes with provider networks and prior authorization requirements. You cannot have both at the same time.

2. Which Medicare Supplement plan is most popular in Illinois? Plan G is the most popular, held by approximately 45% of Illinois Medigap enrollees. It covers virtually all Medicare cost-sharing gaps except the Part B deductible of $257 per year. Plan F is the second most popular but is only available to those who became Medicare-eligible before January 1, 2020.

3. How much does Medicare Supplement insurance cost in Illinois in 2025? At age 65, Illinois residents pay between $47 and $562 per month, depending on the plan and carrier. The most competitive rates include Plan N starting around $101 per month, Plan G starting around $144 per month, and Plan F starting around $164 per month. Premiums vary significantly by carrier and location — comparing multiple quotes is essential.

4. When is the best time to enroll in a Medicare Supplement plan in Illinois? The best time is during your six-month Medigap Open Enrollment Period — which begins when you are at least 65 and enrolled in Medicare Part B. During this window, insurers must offer you coverage at standard rates regardless of your health history. Illinois also has an annual open enrollment opportunity that goes beyond federal requirements — contact Chime Insurance Group to understand your current enrollment options.

5. Does Medicare Supplement cover prescription drugs in Illinois? No. Medicare Supplement plans do not cover prescription drugs. You need a separate Medicare Part D prescription drug plan. Illinois insurers offer 17 stand-alone Part D plans in 2025 with premiums starting at $0 per month. Chime Insurance Group helps you choose both your Medigap and Part D plans together.

6. Can I switch Medicare Supplement plans in Illinois? Outside of guaranteed-issue periods, switching Medigap plans in Illinois typically involves medical underwriting — insurers can charge you more or decline coverage based on your health. However, Illinois's annual open enrollment period gives beneficiaries a limited window to switch with guaranteed issue rights. Contact Chime Insurance Group to understand your current switching options.

7. What does Medicare Supplement Plan G cover in Illinois? Plan G covers Medicare Part A coinsurance and hospital costs, Part B coinsurance and copayments, the first three pints of blood, Part A hospice care coinsurance, skilled nursing facility coinsurance, the Part A deductible, Part B excess charges, and foreign travel emergencies up to plan limits. The only gap is the annual Medicare Part B deductible of $257 in 2026.

8. Is there a Medicare Supplement plan in Illinois that covers everything? Plan F covers all Medicare cost-sharing gaps, including the Part B deductible, making it the most comprehensive option. However, Plan F is only available to Illinois residents who became Medicare-eligible before January 1, 2020. For new Medicare enrollees, Plan G is the most comprehensive available option.

9. Does Chime Insurance Group help with Medicare in Frankfort and Will County, Illinois? Yes. Chime Insurance Group is based in Frankfort, Illinois, and specializes in helping Will County and Chicago suburb residents navigate Medicare Supplement options. We compare plans from multiple Illinois carriers and provide free Medicare consultations in person, by phone, or virtually.

10. How do I get a free Medicare Supplement quote in Illinois? Contact Chime Insurance Group. Our licensed Medicare specialists compare plans from multiple Illinois carriers and help you find the right Medigap coverage for your specific health needs and budget — completely free of charge.

READY TO CLOSE THE GAPS IN YOUR MEDICARE COVERAGE?

Medicare Supplement insurance gives you the financial predictability and comprehensive coverage that Original Medicare alone cannot provide. With over 750,000 Illinois residents already enrolled in Medigap plans — and premiums for comprehensive coverage starting at around $101 to $144 per month — there is a plan that fits your needs and your budget.

Chime Insurance Group makes finding it simple. Our licensed agents in Frankfort, Illinois, compare plans from multiple top carriers, explain your options in plain language, and help you enroll with confidence — at no cost to you.

Get your free Medicare consultation today

Chime Insurance Group serves Medicare beneficiaries across Illinois, including Frankfort, Mokena, New Lenox, Tinley Park, Orland Park, Joliet, Bolingbrook, Romeoville, Chicago, and throughout Will County, Cook County, and the greater Chicago metropolitan area.