WASHINGTON – Americans have been migrating south and west for decades, but it appears they’ve been leaving some high-paying jobs behind.

While there are many pockets of wealth in the South and West, the states with the highest wage earners line the East Coast, according to Census data released Tuesday.

Connecticut, with a median household income of $56,409, supplanted New Jersey as the country’s highest wage state in 2003, the most recent year available. New Jersey slid to second, at $56,356, followed by Maryland, Massachusetts and New Hampshire.

Mississippi had the lowest median income, at $32,397. West Virginia, Arkansas, Louisiana and Montana rounded out the bottom five.

The median household income for the nation was $43,318. Maine, with a median household income of $39,212 ranked 36th.

Census figures show that Southern and Western states have been growing in population much faster than those in the Northeast and Midwest.

But despite those population shifts, the list of wealthiest – and poorest – states in 2003 looks a lot like the list from a decade before.

“You’re going to see those areas – Mississippi, Appalachia – those are just characteristically, throughout history, poorer areas,” said David Waddington, chief of the Census Bureau’s small area estimates branch.

The wage gap among counties was even more pronounced than the one for states.

Los Alamos County in New Mexico, home of the Los Alamos National Laboratory, had the nation’s highest median income, at $93,089. It was followed by Douglas County in Colorado and Loudoun County in northern Virginia.

Buffalo County in South Dakota, home of the Crow Creek Indian Reservation, had the lowest, at $17,003. It was followed by Owsley County in Kentucky and Ziebach County, also in South Dakota.

Most of the wealthiest counties were suburban, and nearly all the poorest ones were rural.

“This is a reflection of a poverty problem in nonmetro areas,” said Dean Jolliffe, an economist at the Department of Agriculture. “These are areas where there really isn’t any economic development going on.”

Jolliffe tracks “persistent poverty” counties, ones in which at least 20 percent of the population have lived below the poverty level for at least 30 years. There were 386 persistent poverty counties in 2000, and 340 were outside metropolitan areas.

None was in the Northeast. Most were in the South.