Knowing where you'll live in retirement can be as important as how much you save.

In three U.S. states, you'd need to spend six figures a year to live comfortably in retirement — far more than in most others, according to a recent GOBankingRates analysis.

In Hawaii, California and Massachusetts, average annual retirement expenses exceed $100,000, with Hawaii topping the list at $129,296. In contrast, retirees in West Virginia need just $58,190 a year — the lowest of any state.

Over a 30-year retirement, the difference in savings needed between Hawaii and West Virginia would be over $1.25 million.

The estimates are based on the average annual retirement costs for Americans ages 65 and older in each state, using Bureau of Labor Statistics estimates for food, shelter, transportation, health care and utility expenses. A 20% cash buffer was added to this total to ensure retirees could live "comfortably," according to the study.

Here's a breakdown of the three states where living comfortably will cost more than six figures, per GOBankingRates' calculations:

Hawaii

• Total annual expenditures: $107,746
• 20% comfort buffer: $21,549
• Cost of a comfortable retirement annually: $129,296

California

• Total annual expenditures: $83,906
• 20% comfort buffer: $16,781
• Cost of a comfortable retirement annually: $100,687

Massachusetts

• Total annual expenditures: $83,501
• 20% comfort buffer: $16,700
• Cost of a comfortable retirement annually: $100,201

The reason why retirement costs are so expensive in these states is largely due to housing, which is typically the biggest expense in Americans' household budgets. All three states have some of the worst housing shortages in the country, which has driven up prices.

Food costs also play a role, especially in Hawaii, an island state where the cost of importing goods is passed on to consumers.

The median annual cost of retiring comfortably is $66,870 for the U.S. as a whole, based on the data. States where you can still retire for under $65,000 a year are largely more rural states in the South, where the cost of living tends to be lower.

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