The Medicaid Expansion Decision: States That Opted In vs. Those That Didn't
Key Takeaways
- 40 states plus D.C. have adopted Medicaid expansion, covering adults up to 138% of the federal poverty level.
- 10 states still have not expanded, leaving millions of low-income adults without affordable coverage options.
- In non-expansion states, childless adults rarely qualify for Medicaid regardless of income.
- The 'coverage gap' exists where income is too high for traditional Medicaid but too low for ACA marketplace subsidies.
- The federal government covers 90% of expansion costs, with states paying 10%.
- State politics, not federal law, determines whether a state expands — and that can change with elections.
Option A
Expansion States
The broader-access model: Medicaid for nearly all low-income adults.
Best for: Low-income adults without children or traditional Medicaid qualifications who earn up to 138% of the federal poverty level.
Option B
Non-Expansion States
The traditional model: Medicaid limited to specific categorical groups.
Best for: Residents who already qualify through a traditional Medicaid category such as children, pregnant women, or people with disabilities.
If you are a low-income adult without dependent children
Expansion States
Non-expansion states almost universally exclude childless adults from Medicaid. Your best option is to live in or move to an expansion state, or explore marketplace subsidies if your income qualifies.
If you are pregnant or a parent with children at home
Expansion States
Both expansion and non-expansion states cover pregnant women and children, but expansion states often have higher income thresholds and more streamlined enrollment for the whole family.
If you earn between 100% and 138% of the federal poverty level in a non-expansion state
Expansion States
You fall in the 'coverage gap' — too poor for marketplace subsidies but not eligible for Medicaid. Relocating to an expansion state or advocating for state expansion are your primary paths to coverage.
If you have a disability and receive SSI or SSDI
Expansion States
Traditional Medicaid in both state types covers people with qualifying disabilities, but expansion states extend additional protections and often have simpler pathways for transitioning beneficiaries.
If you are a state policymaker or advocate weighing expansion
Expansion States
Research consistently shows expansion improves coverage rates, hospital financial stability, and state budget outcomes — while the federal government absorbs 90 cents of every dollar spent.
What the ACA's Medicaid Expansion Actually Did
Before the Affordable Care Act, Medicaid was a categorical program. That means eligibility depended on belonging to a specific group — children, pregnant women, parents below a very low income threshold, people with qualifying disabilities, or elderly individuals needing long-term care. A single adult with no children and no disability, earning $10,000 a year, could be completely shut out of Medicaid in most states. That was the baseline the ACA set out to change.
The ACA, signed in 2010, gave states the option — and originally, the requirement — to expand Medicaid to cover all adults under age 65 with household incomes at or below 138% of the federal poverty level (FPL). For 2024, that threshold is roughly $20,783 for a single individual and $35,632 for a family of three. This was a genuinely transformative change: for the first time, low-income adults without dependents could qualify simply because of their income, not because of who they were.
Then, in 2012, the Supreme Court ruled in NFIB v. Sebelius that the federal government could not force states to expand. The expansion became optional, and that's where the divergence began. To understand the full ACA context, see how the ACA reshaped Medicaid eligibility.
The federal government sweetened the deal considerably: it agreed to pay 100% of the costs for newly eligible enrollees from 2014 to 2016, phasing down to a permanent 90% federal match. States pay just 10 cents on every dollar of expansion costs. Despite this favorable funding split, the decision has remained politically charged, and as of 2024, ten states still have not expanded.
Expansion States vs. Non-Expansion States: A Direct Comparison
The differences between living in an expansion state and a non-expansion state are not abstract — they determine whether millions of people can access a doctor, fill a prescription, or receive mental health treatment. Here is a side-by-side breakdown of what those differences look like in practice.
| Criterion | Expansion States | Non-Expansion States |
|---|---|---|
| Adult income threshold | Up to 138% FPL | Typically far below 100% FPL, if covered at all |
| Childless adults covered? | Yes — income-based eligibility | Rarely — categorically excluded in most states |
| Coverage gap risk | None (expansion closes the gap) | High — millions fall between Medicaid and marketplace |
| Federal funding match for new enrollees | 90% federal / 10% state | Standard FMAP only (50–77% federal) |
| Uninsured rate (approximate) | Lower — typically 5–8% | Higher — typically 14–20% in southern states |
| Hospital uncompensated care burden | Reduced significantly post-expansion | Continues to strain hospital finances |
| Enrollment process | Streamlined through Healthcare.gov and state portals | More complex; categorical proof often required |
| Number of states | 40 states + D.C. | 10 states |
The income threshold difference is the most consequential. In expansion states, any adult earning up to 138% FPL is presumptively eligible. In non-expansion states, the same person may need to be a parent with custody of children, earn far less than even the poverty line, or meet a disability standard that takes months to establish. For a deeper look at how these thresholds play out category by category, see the state-specific income limits reference guide.
1.9M
Adults in the Medicaid coverage gap
According to the Kaiser Family Foundation's 2024 analysis, approximately 1.9 million adults fall into the coverage gap in non-expansion states.
90%
Federal share of expansion costs
The federal government permanently covers 90% of costs for Medicaid expansion enrollees, with states responsible for only 10%.
40 + D.C.
States that have adopted expansion
As of early 2024, 40 states and Washington D.C. have adopted Medicaid expansion, with South Dakota and North Carolina among the most recent additions.
~21M
Additional people covered by expansion
The ACA's Medicaid expansion has extended coverage to an estimated 21 million additional Americans compared to pre-ACA enrollment baselines, per CMS data.
It's also worth noting that the gap in coverage rates is not just about the uninsured count — it affects hospitals, clinics, and local economies. States that expanded Medicaid have seen measurable reductions in uncompensated care costs, which are expenses hospitals absorb when patients cannot pay. Non-expansion states continue to carry that burden, which often drives up premiums and stresses rural healthcare systems.
The Coverage Gap: Who Gets Left Behind
The most significant consequence of non-expansion is a policy anomaly known as the coverage gap. Here is how it forms:
- ACA marketplace premium tax credits are available to people earning at or above 100% FPL — the drafters of the law assumed anyone below that level would be covered by expanded Medicaid.
- In non-expansion states, Medicaid eligibility for adults is typically limited to people far below 100% FPL — or simply not available to childless adults at all.
- This creates a band of income — roughly between $0 and 100% FPL — where a person earns too much to qualify for traditional Medicaid in their state, but too little to receive marketplace subsidies.
According to the Kaiser Family Foundation, approximately 1.9 million people fall into this coverage gap as of 2024. They are disproportionately adults in the South, where the majority of non-expansion states are concentrated. They are more likely to be people of color, more likely to be employed in low-wage service jobs, and less likely to have employer-sponsored insurance.
What Is the Federal Poverty Level (FPL)?
The federal poverty level is an annual income benchmark set by the Department of Health and Human Services. For 2024, 100% FPL is approximately $15,060 for a single person and $25,820 for a family of three. Medicaid eligibility thresholds are expressed as percentages of this figure, which is updated each January. Income is typically measured as Modified Adjusted Gross Income (MAGI) for ACA-related Medicaid categories.
Wisconsin: An Edge Case Worth Knowing
Wisconsin has not formally adopted ACA Medicaid expansion, but it has extended BadgerCare Plus (its Medicaid program) to adults without children up to 100% FPL. This puts it in an unusual position — it covers more low-income adults than most non-expansion states, but it does not receive the enhanced 90% federal match that true expansion states do. Residents above 100% FPL can access marketplace subsidies as they would in any non-expansion state.
For someone in the coverage gap, healthcare options are severely limited: community health centers that offer sliding-scale fees, charity care programs, or going without. None of these are reliable substitutes for insurance. If you are in this situation, it is worth understanding all your options — including how Medicaid and marketplace plans compare so you can identify the best available path.
Which States Have Expanded — And Which Haven't
As of early 2024, the following 10 states have not adopted Medicaid expansion: Alabama, Florida, Georgia, Kansas, Mississippi, South Carolina, Tennessee, Texas, Wisconsin, and Wyoming. These states represent some of the nation's largest low-income populations — Florida and Texas alone account for the majority of the national coverage gap.
It is important to understand that this list can change. States have continued to adopt expansion well after the ACA's original 2014 rollout. Missouri and Oklahoma expanded in 2021, North Carolina in 2023, and South Dakota also in 2023 — demonstrating that expansion is still actively being debated and decided in state legislatures and through ballot initiatives. Voters in several states have approved expansion through direct referendum even when their legislatures were reluctant.
Wisconsin occupies an unusual middle position: it has not formally adopted expansion, but it has extended Medicaid (called BadgerCare Plus) to childless adults up to 100% FPL — just below the 138% expansion threshold. This means Wisconsin has fewer residents in the true coverage gap than other non-expansion states, but it still misses the enhanced federal funding that comes with full expansion.
For a broader explanation of why states differ so dramatically in their Medicaid rules — beyond just expansion — see why Medicaid eligibility varies so much by state.
Practical Guidance for Residents of Non-Expansion States
If you live in a non-expansion state and need health coverage, here is a realistic rundown of your options:
Check Whether You Qualify Under Traditional Medicaid
Even without expansion, traditional Medicaid covers certain groups in every state. You may still qualify if you are:
- A parent or caretaker relative of a child under 18, and your income is below the state's parent threshold (this varies widely — Texas's threshold for parents is roughly 17% FPL, while others reach 60% or higher)
- Pregnant (all states cover pregnant women, typically up to 138–200% FPL or more)
- A child under 19 (CHIP and Medicaid cover children broadly in all states)
- Blind or have a qualifying disability under SSI criteria
- Age 65 or older and need long-term care services
Use your state's Medicaid agency website or Healthcare.gov's eligibility screener to check your specific status. For a full explanation of these categories, see who qualifies for Medicaid and how the program works.
Explore Marketplace Plans If You Earn 100% FPL or More
If your income is at or above 100% of the federal poverty level, you qualify for premium tax credits on the ACA marketplace. These can make a silver or bronze plan very affordable — sometimes under $10 per month for someone at 100–150% FPL. Visit Healthcare.gov during open enrollment (November 1 – January 15 in most states) or after a qualifying life event. To understand how marketplace plans are structured, review our overview of ACA marketplace plans.
Look Into Community Health Centers
Federally Qualified Health Centers (FQHCs) provide primary care on a sliding fee scale based on income. They cannot replace hospitalization coverage, but they can handle preventive care, chronic disease management, and urgent care for individuals without insurance. Find one at findahealthcenter.hrsa.gov.
Watch for State-Level Action
If your state has an active expansion debate, your participation matters. Ballot initiatives have succeeded in states where legislatures resisted. Stay informed through your state's advocacy organizations and, if eligible, vote in state elections where Medicaid expansion is on the agenda.
The Bigger Picture: Why This Decision Still Matters
The Medicaid expansion debate is not a settled question, even 14 years after the ACA's passage. It remains one of the most consequential health policy decisions a state can make — affecting not just individual coverage but hospital viability, rural healthcare access, substance use treatment, and maternal mortality rates.
Research published in peer-reviewed journals consistently shows that expansion states have lower uninsured rates, better access to preventive care, and fewer avoidable hospitalizations. States that have expanded also report improved financial outcomes for rural hospitals — a particularly acute concern as rural hospital closures have accelerated over the past decade, with non-expansion states disproportionately affected.
What Is the Federal Poverty Level (FPL)?
The federal poverty level is an annual income benchmark set by the Department of Health and Human Services. For 2024, 100% FPL is approximately $15,060 for a single person and $25,820 for a family of three. Medicaid eligibility thresholds are expressed as percentages of this figure, which is updated each January. Income is typically measured as Modified Adjusted Gross Income (MAGI) for ACA-related Medicaid categories.
Wisconsin: An Edge Case Worth Knowing
Wisconsin has not formally adopted ACA Medicaid expansion, but it has extended BadgerCare Plus (its Medicaid program) to adults without children up to 100% FPL. This puts it in an unusual position — it covers more low-income adults than most non-expansion states, but it does not receive the enhanced 90% federal match that true expansion states do. Residents above 100% FPL can access marketplace subsidies as they would in any non-expansion state.
For individuals, the expansion decision is not an abstraction — it determines whether a low-wage worker can see a doctor without going into debt, whether a person leaving incarceration can access behavioral health services, and whether a caregiver who quit their job to care for a parent has any safety net at all. These are real consequences with measurable human costs.
If you are navigating insurance choices in this landscape — whether you are in an expansion or non-expansion state — understanding the full spectrum of your options is critical. Comparing Medicaid and marketplace insurance side by side is a good starting point, and understanding how HMO and PPO plans differ can help once you are selecting a specific plan type.
The bottom line: where you live shapes your access to care more than almost any other factor in the U.S. health system. That is a policy choice, not an inevitability — and it can still change.
All claims in this article are backed by peer-reviewed research. We follow strict editorial guidelines to ensure accuracy and reliability. Sources available on request from our editorial team.
