Medicare in Illinois serves about 2.3 million beneficiaries, with 48% enrolled in Medicare Advantage and the remainder on Original Medicare + Medigap. Average Medigap Plan G premium for a new 65-year-old enrollee: $147/mo. Stand-alone Part D plans average $45/mo.
Medicare Beneficiaries
2.3 million
Age 65+ and disabled
MA Enrollment
48%
% on Medicare Advantage
Avg Medigap Plan G
$147/mo
New enrollee, age 65
| Topic | Detail | Notes |
|---|---|---|
| Medicare Advantage plans available | 70+ | Varies by county; check medicare.gov plan finder |
| Top MA carriers | UnitedHealthcare, Humana, BlueCross BlueShield Illinois | Networks differ by county |
| Stand-alone Part D | $45/mo | Required if you have Original Medicare + Medigap |
| Annual guaranteed-issue Medigap switching | No (one-time 6-month window at 65) | No state annual GI rights; Chicago metro is one of the nation's largest and most competitive MA markets. |
Medigap premiums vary by carrier, age, and ZIP code. The 2026 Part B premium is $202.90/month and Part B deductible is $283. Part D out-of-pocket cap is $2,100 in 2026.
Illinois is a tale of two Medicare markets. The Chicago metropolitan area — Cook, DuPage, Lake, and Will counties — is one of the most plan-rich and competitive Medicare Advantage markets in the country, with beneficiaries regularly choosing from 70 or more plans. Northwestern Medicine, Advocate Aurora Health, Rush University Medical Center, and NorthShore University HealthSystem are the major academic and community hospital systems, each with broad MA network participation. BlueCross BlueShield Illinois (BCBSIL) and UnitedHealthcare are the largest MA carriers statewide, and Humana is a strong presence particularly in the collar counties.
Downstate Illinois, particularly rural communities in the southern and central regions, sees significantly fewer MA plan options and more network adequacy concerns. Beneficiaries in communities like Carbondale, Decatur, and Quincy often find Original Medicare with Medigap more practical. Medigap Plan G averages about $147/month in Illinois — moderate for a large urban-rural state. Illinois has no birthday rule or annual Medigap switching protections. The SHIP (Senior Health Insurance Program) through the Illinois Department on Aging is a valuable free resource for beneficiaries navigating plan choices, particularly during the Annual Enrollment Period.
In Illinois, traditional Medicare combined with a Medigap supplement (typically Plan G or N) plus a stand-alone Part D plan provides nationwide access with predictable costs. Plan G covers everything except the $283 Part B deductible.
Medicare Advantage (Part C) plans bundle Medicare Parts A, B, and usually D into one private plan, often with $0 premium beyond Part B. Trade-offs include network restrictions and prior authorization. 48% of Illinois beneficiaries currently choose MA.
No state annual GI rights; Chicago metro is one of the nation's largest and most competitive MA markets.
💡 Illinois Pro Tip
Illinois beneficiaries in the Chicago metro area typically have access to 70 or more Medicare Advantage plans. Mid-sized cities like Rockford, Peoria, and Springfield generally offer 25 to 45 plans. Rural southern Illinois counties may have only 10 to 20 options due to limited provider network density.
The average Medigap Plan G premium for a 65-year-old in Illinois is approximately $147 per month. Chicago-area premiums may run slightly higher, while downstate communities often see lower rates. Multiple carriers compete in Illinois, so comparing quotes from BCBSIL, Cigna, and Mutual of Omaha is recommended.
Illinois does not have a birthday rule or annual guaranteed-issue protections for Medigap. Switching outside of your initial 6-month open enrollment at 65 or a qualifying federal event requires medical underwriting. Illinois residents can contact the SHIP counseling program for free guidance on Medigap options.
Beneficiary counts and MA enrollment percentages from CMS state-level Medicare data; premium averages from 2026 carrier rate filings for Illinois. Verify current plan costs at medicare.gov before enrolling.
Jennifer Walsh
Editorial Lead, Health & Medicare
This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.
Reviewed May 2026
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