Mississippi is the poorest state in the nation, with median household income of $36,919, while Maryland, with median income of $70,004, is the richest state, according to the 2011 American Community Survey from the U.S. Census Bureau. The poorest states are almost entirely located in the South, according to an analysis of the census data by 24/7 Wall Street, while the more prosperous states are spread across the country.

Median U.S. household income declined for the second straight year, according to the census data, dropping to $50,502 in 2011, more than 8 percent below the 2007 pre-recession peak. Twenty-seven states had household income levels lower than the U.S. median, while 19 states had higher income levels.

Vermont was the only state where median income increased. Income fell in 18 states and remained statistically unchanged in 31 states.

Household income was higher than the U.S. median in the District of Columbia. Seven of the nation’s 10 most affluent counties are located in the Washington, D.C., area, according to The Washington Post.

Following Mississippi, the other states among the five poorest states in the country, according to 24/7 Wall Street, are West Virginia, median household income, $38,482; Arkansas, median income, $38,758; Kentucky, median income, $41,141; and Alabama, median income, $41,415.

Following Maryland, the other states among the five richest states are Alaska, median household income, $67,825; New Jersey, median income, $67,458; Connecticut, $65,753; and Massachusetts, $62,859.