How to Map a PACE Expansion: Data and Steps

To map a PACE expansion, plot centers and service ZIP codes, estimate the eligible pool outside them, and test drive times from candidate sites. Then check competing organizations and state rules, because CMS and the State administering agency must approve any change in the designated service area.

The PACE rules that shape your map

Federal eligibility rules sit in 42 CFR §460.150. Medicare.gov lists the same tests in plain language. Each one points to a different map layer.

Most enrollees are still dual eligible. CMS says "most of the participants who are in PACE are dually eligible" for Medicare and Medicaid.

PACE is not offered everywhere. Medicare.gov says it is only available in some states that offer PACE under Medicaid. For context, the National PACE Association's directory, viewed November 2026, reports 206 programs serving more than 98,800 participants in 33 states and DC. These are NPA's figures, not CMS's.

How PACE service areas are defined and expanded

Each PACE program agreement designates a service area. It may be identified by county, ZIP code, street boundaries, census tract, block or tribal jurisdictional area. California and Washington both define service areas by ZIP code, so plan at the ZIP level.

A PACE organization must run at least one PACE center in, or contiguous to, its service area, with room for routine attendance. Under §460.98(e)(2), it must add centers, staff or services if needed to keep services accessible and adequate.

The federal expansion process

1. Get state approval first. The organization must get approval from both the State Medicaid agency and the State Administering Agency (SAA). Without a signed State assurance, CMS treats the application as incomplete and will not evaluate it.
2. Apply in HPMS. CMS says applicants complete both initial and service area expansion applications in HPMS. The application must describe the proposed service area.
3. Meet the timing rules. CMS and the state approve expansions only after the first trial period audit and any required corrective action plan. CMS has 45 days to act on a service area expansion or a new center, and 90 days for both together. Acting means approving, denying or asking for more information.
4. Pass a readiness review for new sites. For a new center, the SAA conducts a readiness review of the new site while the review clock is stopped.
5. Amend Appendix C. If CMS approves, Appendix C of the program agreement is amended to show the new area or site.

CMS, in consultation with the state, may exclude an area already covered by another PACE program agreement. The National PACE Association's application process page summarizes these steps (NPA guidance, not regulation).

CMS accepts applications on quarterly deadlines. Its July 22, 2026 rural PACE memo points to a January 15, 2026 HPMS memo for the 2026 dates. The memo is in the zip file on that CMS page (LeadingAge copy).

Public data for PACE expansion planning

Step-by-step: mapping a PACE expansion

Step 1: Map current PACE centers and service ZIP codes

1. Download your state's PACE ZIP list. California's DHCS says enrollees must reside in one of the service areas and ZIP codes listed.
2. Join ZIP codes to ZCTA boundaries. ZCTAs are "generalized areal representations" of ZIP codes, and not every ZIP code has one. See ZCTA vs. ZIP code.
3. Geocode each PACE center. NPA's directory lists only program names and cities, so get each center's street address from the program's own site first.
4. Add CMS enrollment. The CPSC file readme lists "National PACE" among its organization types. It reports enrollees by legal county of residence. Small counts are shown as * (10 or fewer).

GeoChat AI is one free option for this step, with no credit card required. As of November 2026, GeoChat Atlas includes PACE layers: PACE sites, PACE coverage by county and PACE service ZIP codes. The platform is new; the current version is GeoChat Atlas (version 2).

Step 2: Estimate the eligible pool by ZIP code or county

Only the State administering agency makes the level-of-care finding (§460.150(b)(2)), so you can only map proxies. Label yours as a proxy.

1. Pull table B18106 from the ACS 2020–2024 5-year release for ZCTAs or tracts. Self-care difficulty means difficulty bathing or dressing.
2. Note its age groups: 5–17, 18–34, 35–64, 65–74, and 75 and over. There is no 55–64 group.
3. Pick one rule for ages 55–64 and write it down: - 65 and over only. Add the 65–74 and 75-and-over groups. This leaves out people 55 to 64. - Apportion 35–64. Apply the 35–64 self-care rate to the 55–64 population from B01001, which has 55–59, 60–61 and 62–64 groups. This assumes ages 55 to 64 share the rate of the whole 35–64 group. - Use microdata. ACS PUMS has age in single years and self-care difficulty. Its smallest geography is the PUMA, with 100,000 or more people. Use it to check regional totals, not to map ZIP codes.
4. Keep the margins of error with each estimate. See ACS 5-year estimates.
5. Add CMS dual counts as context, not as the denominator. The MMCO snapshot gives county counts by dual status through September 2025.

As of November 2026, GeoChat Atlas also has estimates of people 55 and over who may be eligible for PACE. They are proxies built from ACS self-care difficulty and do not check nursing-home level of care or PACE service areas. Because B18106 has no 55–64 group, GeoChat uses the apportioning option above. It scales the 35–64 self-care count by the 55–64 share of people aged 35–64. Its AI chat lets you drill into ZIP codes and compare regions.

Step 3: Find gaps outside current service areas

1. Flag ZCTAs with a sizable proxy count but no PACE coverage.
2. Rank them by proxy count and by proxy rate per 1,000 residents 55 and over.
3. Overlay county CPSC enrollment to see where programs already reach. The CPSC file has no field marking which counties are inside a contract's approved service area.
4. Group adjacent gap ZIP codes into candidate areas. The organization must have "at least one PACE center either in, or contiguous to, its defined service area".

Step 4: Test drive times from a candidate center

CMS's rural PACE memo says the agency "does not have a specific travel time requirement", but states may set their own. The memo is in that page's zip file (LeadingAge copy).

California's PACE Policy Letter 23-01 allows a drive of at most 60 minutes one way to the PACE center from participants' homes. The letter also calls it the adult day health center. Applicants must use commute hours of 6:00 to 8:00 a.m. and 2:00 to 4:00 p.m.

1. Geocode two or three candidate sites.
2. Build drive-time areas at your state's threshold, using traffic for the stated hours. See drive-time access.
3. Test every ZIP code in the candidate area. Record the point you measured from.
4. Drop ZIP codes that fail. DHCS runs its own review and requires removal of ZIP codes that miss the drive-time rule.
5. Recount the eligible-pool proxy inside the ZIP codes that pass.

Step 5: Check competing PACE organizations and state approval rules

1. List every existing or pending PACE organization in your candidate ZIP codes. Washington requires new applicants to identify overlap with an existing or pending PACE organization.
2. Read your state's overlap rule. Washington allows only a single PACE organization per service area ZIP code. King County is the exception: two are allowed, based on an assumed 10% penetration rate.
3. Expect a response from incumbents. California decides overlap at the ZIP code level, and existing or pending organizations may file a counter-feasibility study within 30 days of notice.
4. Confirm the state is taking applications. California paused new PACE organization and service area expansion applications from November 20, 2025, until at least November 19, 2027. Applications already received and in review are not affected.
5. Build the feasibility study the state asks for. California and Washington both require an estimate of PACE-eligible individuals, the method behind it, competitive factors and projected capture rates.

Step 6: Document the map for the application

California's application needs a service area map with the PACE center clearly marked, plus boundaries and traffic arteries. Put a methods note under each map:

1. ACS release and table IDs, such as B18106 and B01001 from the 2020–2024 5-year estimates.
2. Your rule for ages 55–64.
3. ZIP list date, ZCTA vintage and any crosswalk quarter.
4. CPSC month and its suppression rule.
5. Drive-time tool, threshold and departure times.

Limits to state in your analysis

• ACS cannot identify nursing-home level of care. The State administering agency makes that finding. Self-care difficulty is a survey answer, not a clinical assessment.
• ACS dual proxies are not CMS counts. B27010's category is "With Medicare and Medicaid/means-tested public coverage", which is self-reported and broader than Medicaid. Use the MMCO snapshot for administrative county counts.
• Disability tables leave out institutions. B18106 covers the civilian noninstitutionalized population 5 years and over, so nursing home residents are not in it.
• ZIP codes are not ZCTAs. Service areas use USPS ZIP codes, while ACS uses ZCTAs. PO Box-only ZIP codes are not in the HUD crosswalk, so place them by hand.
• CMS enrollment is county-level and partly suppressed. Cells shown as * (10 or fewer) carry no number, so summed county totals understate enrollment.
• State approval decides the final map. States can set travel rules, overlap limits and application pauses on top of federal rules.

Common mistakes

• Calling the proxy "eligible people." Label it as an estimate of potential need, and name the tables.
• Hiding the 55–64 step. B18106 has no 55–64 group, so state how you handled it.
• Measuring midday drive times. Use the hours your state specifies.
• Treating CPSC counties as service areas. CMS's October 2026 MA contract service area file lists every "National PACE" contract as covering the entire US. Use the state ZIP list for boundaries.
• Checking only current competitors. Washington and California also ask about pending organizations.
• Assuming a federal drive-time standard. CMS has none; check your state.

For related methods, see the CHNA access-gap mapping guide and our California county healthcare access data.