Household income in Maine increased again last year, but it still lags behind national and regional levels, particularly in the state’s northern and western counties.

The state’s median household income was $56,227 in 2017, an almost 4 percent increase from 2016, according to statistics released Thursday by the U.S. Census Bureau. The estimate has a margin of error of plus or minus 2 percent.

Maine’s rate of income growth outpaced the national average, but the median U.S. household income was $60,336, about $4,000 higher than in Maine. In New England, the median income was about $71,494.

The new income estimates are part of the American Community Survey, an annual look at social and economic indicators at the state, county and city level.

“As you might expect, the latest increase in median household income in Maine is consistent with other data we’re seeing reflecting the strong economy in 2017,” said Maine state economist Amanda Rector.

“While Maine’s demographic composition poses a challenge for the state, employment and income continue to grow,” she added. “In fact, Maine’s median household income made up ground – relative to the United States and other New England states – in 2017, increasing by a larger percentage from 2016 than the U.S. or the rest of New England.”

Even so, median income levels in southern Maine are considerably higher than in the rural north and west, although county-level statistics are not as reliable as state-level figures.

In Cumberland County, the location of Maine’s largest city, the median household income rose more than 8 percent over eight years, to $72,000 last year. In southernmost York County, the median household income was about $66,400, more than $10,000 above the statewide median.

Most state households outside the coastal south are living on income well below the median.

Aroostook County had the lowest median income, at $43,015 a year. Households in Androscoggin County had a median of $48,286 a year, Penobscot County $50,349 a year and Kennebec County $53,073 a year.

Maine placed 29th, between Georgia and Kansas, on a ranking of income for the 50 states and District of Columbia. Almost half the states had median income between $50,000 and $60,000 a year.

While Maine and many other states have not kept pace with the national median income, poverty has declined. Nationally, the poverty rate dropped to 13.4 percent in 2017, down almost three points from five years before.

The percentage of Mainers living in poverty declined by the same degree, to 11 percent last year from around 14 percent in 2013.