KFF’s new interactive maps illustrate ACA Marketplace enrollment and changes in enrollment by congressional district and state. Marketplace enrollment declined in most congressional districts between 2025 and 2026, with two-thirds of the decline (67%) occurring in Republican-held congressional districts.

KFF’s new interactive maps illustrate Medicaid enrollment by congressional district and eligibility group. In half of Republican congressional districts, at least 20% of residents are enrolled in Medicaid, and in half of Democratic districts, at least 25% are enrolled.