A Medicare Advantage service area is the group of counties the Centers for Medicare & Medicaid Services (CMS) has approved for a specific plan to operate in. You can only enroll in a plan whose service area includes your home address, your provider network is built around that geography, and if you move out of it or the plan pulls out of your county, you get a Special Enrollment Period to pick something new. Everything else about how these plans work — networks, travel coverage, even your right to buy a Medigap policy later — flows from that county-based boundary.
How the Service Area Is Drawn
For local Medicare Advantage plans, the building block is the county. CMS defines a service area as one or more counties in which an eligible person may enroll in a particular plan.1eCFR. 42 CFR 422.2 – Definitions Regional Medicare Advantage plans cover broader multi-county or multi-state regions, but the local plans most people see during enrollment are drawn county by county.
The county integrity rule is what keeps insurers from cherry-picking neighborhoods. Under 42 CFR § 422.2, a local plan’s service area must generally consist of one or more full counties. An insurer that wants to serve any part of a county generally has to serve the whole thing.1eCFR. 42 CFR 422.2 – Definitions CMS will consider partial-county service areas only in narrow cases where the insurer can show the partial coverage is necessary, nondiscriminatory, and in the best interests of beneficiaries. Approval is the exception.
Before a plan reaches the market, the insurer must hold state authorization to bear risk and receive CMS certification confirming the plan meets federal network, financial, and administrative standards.2eCFR. 42 CFR Part 422 – Medicare Advantage Program – Section: 422.502 Evaluation and Determination Procedures Once approved, the plan must be available to every eligible person who lives inside the service area. If your address is in, you can enroll. If it isn’t, you can’t, no matter how close you live to the line.
Finding Out Which Plans Cover Your Address
The fastest way to see the plans available where you live is to enter your zip code at the Medicare Plan Finder at medicare.gov/plan-compare. The tool lists every plan authorized to operate at your location with premiums, benefits, and star ratings.
Your enrollment application has to include a physical street address.3eCFR. 42 CFR Part 422 – Medicare Advantage Program – Section: 422.50 Eligibility to Elect an MA Plan A P.O. box does not count. If you list one, the plan must treat the enrollment as incomplete and ask for documentation of where you actually live.4Centers for Medicare & Medicaid Services. CY 2026 Medicare Advantage Enrollment and Disenrollment Guidance Acceptable proof includes voter registration records, driver’s license records, tax records, and utility bills tied to the physical address. If there’s a dispute, the plan applies your state’s residency laws. Getting the address right at the start avoids claim denials and disenrollment problems later.
What Care Is Covered Inside and Outside the Area
Covering a whole county on paper is not enough. CMS enforces network adequacy standards that set maximum travel times and distances for each specialty, adjusted for how urban or rural the county is. Counties fall into five categories, from large metro to counties with extreme access considerations, with the strictest limits in dense areas and the loosest in remote ones.5eCFR. 42 CFR 422.116 – Network Adequacy In a large metro county, for example, at least 90 percent of enrollees must have a primary care provider within 10 minutes or 5 miles; in a rural county, the standard is 85 percent within 40 minutes or 30 miles. If a plan’s network doesn’t hit the marks for a county, CMS can refuse to include that county in the service area.
Once you’re enrolled, the service area shapes routine care. Non-emergency, in-network care happens inside the plan’s geography. If you visit an out-of-network specialist in another state for a scheduled appointment, the plan generally has no obligation to cover it unless you have specific out-of-area benefits.
Emergencies are the hard exception. Every Medicare Advantage plan must pay for emergency and urgently needed services regardless of network status and regardless of prior authorization.6eCFR. 42 CFR 422.113 – Special Rules for Emergency and Urgently Needed Services Plans must also cover renal dialysis received from noncontracting providers while you’re temporarily outside the service area, along with post-stabilization care after an emergency.7eCFR. 42 CFR 422.100 – General Requirements The noncontracting provider is paid at least what Original Medicare would have paid and must accept that as payment in full, so you can’t be balance-billed for the difference.
Some plans offer visitor or traveler programs that extend non-emergency coverage to Medicare-participating providers outside the service area for a defined period. These vary widely. Check your plan’s Evidence of Coverage before you assume a long trip is covered.
Moving Permanently vs. Traveling Temporarily
A permanent move to an address outside your plan’s service area triggers a Special Enrollment Period. Notify your plan before the move and the SEP starts the month before you relocate and runs for two full months after. If you notify the plan after the fact, the SEP starts when you move and lasts two months.8Medicare.gov. Special Enrollment Periods The window is short. Start comparing plans before the truck is loaded, not after you unpack.
Temporary absences work under a different rule. If you leave the service area without permanently moving, your plan must disenroll you after six consecutive months away, effective the first day of the month after the six-month mark.9eCFR. 42 CFR 422.74 – Disenrollment by the MA Organization Some plans stretch that to as much as 12 months through a visitor program that lets you use Medicare-participating providers outside the area at in-network cost-sharing.4Centers for Medicare & Medicaid Services. CY 2026 Medicare Advantage Enrollment and Disenrollment Guidance If you spend winters elsewhere, confirm the specifics in the Evidence of Coverage before relying on it.
When a Plan Leaves Your County
Plans reevaluate their service areas every year. If an insurer decides a county is no longer viable or it can’t maintain an adequate provider network there, it can withdraw. When that happens, the plan must send written notice to affected enrollees at least 90 days before the non-renewal takes effect. For a plan exiting on January 1, the notice should arrive by early October.
Affected members get a Special Enrollment Period running from December 8 through the last day of February.8Medicare.gov. Special Enrollment Periods You can enroll in a different Medicare Advantage plan in your area or return to Original Medicare with no late-enrollment penalties. If no other Medicare Advantage plan serves your county, which happens more often in rural areas, Original Medicare plus a standalone Part D drug plan is the fallback.
Your Medigap Guaranteed Issue Right
When your Medicare Advantage plan leaves your service area or terminates, federal law gives you guaranteed issue rights to buy a Medigap supplemental policy. The insurer cannot deny you coverage or charge more based on your health history. The right covers Medigap Plans A, B, C, F, K, and L where they’re available in your state. Plans C and F are closed to anyone who first became eligible for Medicare on or after January 1, 2020. Plan N is not included, and access to Plans D and G under the guaranteed issue right depends on when you first became Medicare-eligible.10Centers for Medicare & Medicaid Services. NAIC Q&A and Follow-Ups
Keep the disenrollment notice from your departing plan. It’s proof of the guaranteed issue right when you apply to a Medigap insurer. The window aligns with the same December 8 through end-of-February SEP, so act quickly.
Long-Term Care Residents
People in skilled nursing facilities, psychiatric hospitals, rehabilitation hospitals, long-term care hospitals, and similar institutional settings are treated differently for service-area purposes. Federal rules classify someone as institutionalized if they continuously reside, or are expected to reside for 90 days or more, in one of these facilities.11eCFR. 42 CFR Part 422 – Medicare Advantage Program The facility’s address functions as the person’s residence.
Institutionalized residents can join a Medicare Advantage plan, switch to a different one, or return to Original Medicare at any time while they’re in the facility. That open window continues for two full months after they move out.12Medicare.gov. Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods
One boundary worth naming: incarcerated individuals are excluded from Medicare Advantage service areas. Facilities where people are incarcerated are not considered part of any plan’s service area.1eCFR. 42 CFR 422.2 – Definitions