Howard County had the state's highest median household income at $101,940 in 2009, while Allegany County came in last at $36,491 among Maryland counties surveyed, according to 2009 American Community Survey data, which only includes areas with populations of 65,000 or more.

The Census Bureau collected data from 15 of Maryland's 23 counties and Baltimore City and reported the $65,449 gap. Baltimore City's median household income was $38,772.

Maryland is statistically tied with New Jersey and Alaska for the highest median household income in the country, despite a slight decrease from $69,844 in 2008 to $69,272 in 2009, the Census Bureau reported. While 35.9 percent of Maryland households earned less than $50,000, the rest earned more, according to the Census Bureau.

Maryland's median household income topped Virginia's $50,221 and D.C.'s $59,290. The national average was $59,330.

The country was in an economic recession during about half the time period used by the census. The recession, which began in December 2007, ended in June 2009, according to the National Bureau of Economic Research. In 2009, Maryland's unemployment rate rose by 2.7 percent to 8 percent, according to census data.

Although the disparity in the Maryland counties' incomes may look alarming, differences in location and costs of living in the counties translate into gaps in income levels between metropolitan Howard County and more rural Allegany County, said economist Mark Goldstein of the Maryland Department of Planning.

"If there is true, stark inequality in any region, the economy starts to stagnate," Goldstein said. "And that's certainly not the case in Maryland." Allegany County has not enjoyed the long-term prosperity of other counties, said Bretta Reinhard, the county's public information officer. "

Allegany County government is fortunate to have a number of dedicated individuals striving to return Allegany County to its prime," she said."Hopefully, the county will increase in prosperity in the near future."

Maryland's income gap was also narrower than that of the United States as a whole, the Census Bureau reported.

Regardless, Gov. Martin O'Malley wants to strengthen the middle class to combat any income inequality, said Shaun Adamec, O'Malley's press secretary.

"It's obviously not a trend we want to see in Maryland," Adamec said, "but we're addressing it by championing initiatives for the middle class and strengthening their safety net."

Among the initiatives mentioned by Adamec were tax credits for businesses, a Medicaid expansion and small business loans to expand and create jobs. O'Malley wants to strengthen and grow the middle class, Adamec said.