ACA Medicaid expansion enrollment likely still over 20 million, but it'd be nice for CMS to post an official update...

Thu, 07/17/2025 - 12:10pm

Now that I've finally completed overhauling & updating my House District Healthcare Enrollment Pie Chart project with the latest data, I wanted to address a rather frustrating elephant in the room.

For most of the healthcare programs involved, the enrollment data is now reasonably up to date:

ACA Qualified Health Plan (QHP) enrollment is as of February 2025 via official Centers for Medicare & Medicaid Services (CMS) public use files.
ACA Basic Health Plan (BHP) enrollment is as of April 2025 (NY), May 2025 (OR) or July 2025 (MN) via each state's health department monthly reports.
Uninsured population estimates have been extrapolated from the 2023 American Community Survey through December 2024 via the National Health Interview Surve
Traditional Medicaid updated to March 2025 via CMS's monthly reports
Children's Health Insurance Program (CHIP) enrollment is as of March 2025 via CMS's monthly reports.
Medicare enrollment (Fee for Service, Advantage & Dual Eligible) is as of March 2025 via CMS's monthly reports.

HOWEVER, there's one subset of the above which is still frustratingly out of date, and it's one of the most important datasets at the moment given the massive amount of concern over it caused by the recently-passed H.R. 1, aka the "One Big Beautiful Bill Act," aka the MAGA Murder Bill: Enrollment in Medicaid via ACA expansion specifically.

This is especially frustrating because total enrollment in Medicaid (including the ACA expansion population) is available as of March 2025, but as of this writing, official data for the ACA expansion subset has been frozen as of June 2024 for over six months now (that is...since the Biden Administration was still in office).

The good news is that I've been able to cobble together more recent ACA expansion enrollment for about half of the 40 states (+DC) which participate in the program. The bad news is that I haven't been able to acquire more recent data for the other half:

Here's what it looks like when I break out the official June 2024 CMS report and then update each of the states which have more recent data available:

As you can see, across the 22 states for which I have more recent data, expansion enrollment has only dropped by an average of 1.8% since last June. Most of the states have actually dropped by perhaps 5% or so on average, but this is almost completely canceled out by North Carolina, which has seen their Medicaid expansion population continue to ramp up by nearly 40% year over year, adding over 188,000 people to their tally.

I have no idea what things look like in the other half of the states, but assuming a similar ~2% drop, total enrollment nationally would be around 20.5 million today. If I don't include North Carolina, the avg. drop for the other 20 states is around 4%, which would translate into around 20.1 million.