Medicare in Montana serves about 270,000 beneficiaries, with 29% enrolled in Medicare Advantage and the remainder on Original Medicare + Medigap. Average Medigap Plan G premium for a new 65-year-old enrollee: $145/mo. Stand-alone Part D plans average $43/mo.
Medicare Beneficiaries
270,000
Age 65+ and disabled
MA Enrollment
29%
% on Medicare Advantage
Avg Medigap Plan G
$145/mo
New enrollee, age 65
| Topic | Detail | Notes |
|---|---|---|
| Medicare Advantage plans available | 15+ | Varies by county; check medicare.gov plan finder |
| Top MA carriers | UnitedHealthcare, Humana, Blue Cross Blue Shield Montana | Networks differ by county |
| Stand-alone Part D | $43/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; very low MA penetration due to vast rural geography making provider networks difficult to build. |
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.
Montana has one of the lowest Medicare Advantage enrollment rates in the country at roughly 29%, driven by the state's vast rural geography that makes provider-network-based managed care plans impractical across most of the state. Billings, Missoula, Great Falls, and Bozeman are the main population centers where MA plans have meaningful provider networks. Billings Clinic and SCL Health (now Intermountain Montana) serve the eastern and south-central regions, while Providence St. Patrick Hospital anchors Missoula. In the many small ranching and farming communities across eastern Montana, northern plains, and mountain valleys, Original Medicare with Medigap is far more functional because beneficiaries may need to travel to regional centers and cannot be constrained by HMO networks.
Montana's Medigap Plan G premiums average about $145/month — moderate for a rural mountain state. The state lacks birthday rule or anniversary rule protections, so the 6-month open enrollment window at 65 is the key guaranteed-issue opportunity. Blue Cross Blue Shield of Montana has historically been a strong Medigap carrier in the state. Part D access can be challenging in remote areas, where mail-order pharmacy is often the most practical option. Montana's growing Bozeman market, fueled by out-of-state migration from California and the Pacific Northwest, is creating more competitive MA plan options in Gallatin County.
In Montana, 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. 29% of Montana beneficiaries currently choose MA.
No state annual GI rights; very low MA penetration due to vast rural geography making provider networks difficult to build.
💡 Montana Pro Tip
Montana has one of the smallest Medicare Advantage markets in the continental U.S., with typically 15 or more plans available in population centers like Billings, Missoula, and Great Falls. Most rural Montana counties may have only 5 to 10 MA plan options, which is the primary reason the majority of Montana's Medicare beneficiaries choose Original Medicare with Medigap.
The average Medigap Plan G premium for a 65-year-old in Montana is approximately $145 per month. Blue Cross Blue Shield of Montana, Mutual of Omaha, and UnitedHealthcare/AARP are among the carriers offering Plan G in the state.
Montana does not have a birthday rule, anniversary rule, or annual guaranteed-issue protections for Medigap. Outside of your initial 6-month open enrollment at 65 or qualifying federal events, insurers can apply medical underwriting. Given Montana's limited MA alternatives, maintaining Medigap coverage once enrolled is particularly important.
Beneficiary counts and MA enrollment percentages from CMS state-level Medicare data; premium averages from 2026 carrier rate filings for Montana. 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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