Congressional District Interactive Map: People with Medicare and Medicaid (Dual-Eligible Individuals)
The recently passed budget resolution targets cuts to Medicaid of up to $880 billion or more over a decade to help pay for tax cuts. Major cuts to Medicaid may impact coverage for the almost 1 in 5 Medicare beneficiaries (11.9 million) who are also enrolled in Medicaid. For people covered under both programs (“dual-eligible individuals”), Medicare is the primary payer and covers medical acute and post-acute care, including skilled nursing facility services and home health care. Medicaid wraps around Medicare coverage by paying Medicare premiums and in most cases, cost sharing. Most dual-eligible individuals (8.5 million people in 2025) are “full-benefit” enrollees, which means they are eligible for Medicaid benefits that are not otherwise covered by Medicare, including long-term care, vision, and dental. The remaining 3.4 million dual-eligible individuals, “partial-benefit” enrollees, are eligible for Medicare premiums and often, cost sharing assistance, but not for full Medicaid benefits.
It is unclear what policies might be included in the reconciliation proposals, but significant reductions in Medicaid spending would have potential implications for Medicare beneficiaries who account for nearly 30% of Medicaid spending. The interactive maps below illustrate how many people are enrolled in Medicare and Medicaid in each congressional district, including the number of people receiving full Medicaid and partial Medicaid benefits. Key takeaways include:
- There are at least 7,300 dual-eligible individuals living in each of the 435 congressional districts, with enrollment as high as 81,300 in some districts.
- In each congressional district, there are at least: 4,100 full-benefit dual-eligible individuals and 100 partial-benefit dual-eligible individuals.
- The average number of dual-eligible individuals is 24,700 in Republican districts and 30,000 in Democratic districts.
- The share of dual-eligible individuals with full Medicaid benefits varies across congressional districts, ranging from 30% to 100%.
- The top 10 Republican districts with the highest number of dual-eligible individuals are: FL26 (58,800); KY05 (58,000); FL27 (56,300); NY11 (53,000); FL28 (51,100); WV01 (48,500); CA01 (46,300); NY21 (45,700); CA22 (41,500); and AR01 (40,900).
- The top 10 Democratic districts with the highest number of dual-eligible individuals are: NY13 (81,300); NY15 (73,700); NY08 (71,600); NY06 (64,800); ME02 (63,300); NY14 (57,800); NY09 (57,300); CA34 (56,500); MA01 (56,400); and NY10 (55,600).
Methods |
| Data: To calculate Medicaid enrollment by eligibility group and congressional district, this analysis uses the KFF analytic file that merged the 2021 Master Beneficiary Summary File (MBSF) Base and the 2021 Transformed Medicaid Statistical Information System (T-MSIS) Analytic Files (TAF) Research Identifiable Files (RIF) file using a Chronic Conditions Warehouse (CCW) beneficiary identifier crosswalk and Centers for Medicare & Medicaid Services Medicare Monthly Enrollment data for January 2025 (downloaded in April 2025).
Dual-Eligible Individual Inclusion criteria: Estimates include dual-eligible individuals in 50 states and the District of Columbia if (1) they were in both the MBSF and T-MSIS files using the CCW crosswalk, and (2) Dual-eligible individuals are assigned full-benefit status and partial benefit status using an “ever” approach and a hierarchy by giving priority to the full-benefit status. Individuals were a full-benefit dual-eligible individual in each year using the Medicare monthly DUAL_STUS_CD with values of 02,04,08 or the Medicaid monthly code DUAL_ELGBL_CD with values of 02,04,08 or the monthly code RSTRCTD_BNFTS_CD_03 values of 1,A,D,4,5,7. If not a full-benefit dual-eligible and the individual had DUAL_STUS_CD with values of 01,03,05,06 or the Medicaid monthly code DUAL_ELGBL_CD with values of 01,03,05,06 or the monthly code RSTRCTD_BNFTS_CD_03 values of 2,3,C,6,E,F they were assigned partial-benefit status. For this analysis, we excluded dual-eligible individuals who only had CHIP eligibility in the year. Assigning Dual-Eligible Individuals to Congressional Districts: This analysis used the Missouri Census Data Center’s Geocorr 2022 tool to create a zip code-to-congressional district crosswalk and a county-to-congressional district crosswalk. Using those crosswalks, we assigned dual-eligible individuals to 119th congressional districts in the T-MSIS data. In some cases, a county or a zip code can be split among multiple congressional districts. In those cases, enrollees were randomly assigned to a congressional district based on an allocation factor from the Geocorr 2022 tool that is calculated using the 2020 decennial census. For each state, we calculated the percentage of people living in a zip code that aligned with a single congressional district and the percentage of people living in a county that aligned with a single congressional district. In most states, the zip code alignment was better, and we used the zip code crosswalk. In 9 states (AL, IA, KY, MS, MT, NC, NE, RI, and WV), the county alignment was better, so we used the county code crosswalk. We applied the T-MSIS distributions of dual-eligible individuals by benefit status and congressional district to the CMS Medicare administrative enrollment data. Those data report monthly enrollment for dual-eligible individuals. The sum of full-benefit and partial-benefit dual-eligible individuals enrolled may not add to total dual-eligible enrollment due to rounding. The sum of dual-eligible individuals across congressional districts may not add to state and national totals published in other KFF resources due to rounding. |
This work was supported in part by Arnold Ventures. KFF maintains full editorial control over all of its policy analysis, polling, and journalism activities.