BackgroundThere are 5.5 million people living with dementia in the United States (US), with the cost of unpaid care making up a significant portion of the care costs.ObjectiveSummarize variation in the cost of dementia care across the US and examine the association between medical spending and costs of unpaid care at the state level.MethodsWe estimated total cost for dementia by combining recent medical spending estimates from the Disease Expenditure project and unpaid care cost estimates from Lastuka and colleagues. Hours of unpaid care were valued as the hourly wage of a home health aide. We used linear regression to measure the association between the cost of unpaid care and medical spending. The spending that would have occurred if unpaid care had been provided by professional home health care workers was used to measure the cost of unpaid care.ResultsThe annual cost of care attributable to dementia in 2019 was 3,502 (95% uncertainty interval [UI] 46,135-60,594) per case. The contribution of unpaid care to total costs varied by state, ranging from 70.2% (95% UI 64.3-75.4) in the District of Columbia to 89.9% (95% UI 87.8-91.5) in Arizona. We found that higher costs of unpaid care were associated with lower medical spending on nursing facility care.ConclusionsThe large variation in total costs of dementia shows that the economic burden of dementia care is distributed unevenly throughout the US.