Health-care spending in the U.S. averaged $6,815 per person in 2009. But that figure varies significantly across the country, for reasons that go beyond the relative healthiness, or unhealthiness, of residents in each state.

The states that spend the most on health care for each resident are mostly in the Northeast. They are led by Massachusetts, a fact several Republicans used to criticize GOP presidential candidate Mitt Romney during the 2012 primaries because as governor Mr. Romney had signed the state's health-care...