Howard County households are among the most prosperous in the nation, according to results from a recently released survey.

Income data from the American Community Survey, an annual data collection project run by the Census Bureau to supplement the once-a-decade census, shows that Howard County has the second-highest median household income in the nation.

At $108,844 in 2012, Howard County's median income was second only to Loudoun County, Va., which last year had a median income of $117,876. Trailing Howard County are Fairfax County, Va., Hunterdon County, N.J., and Arlington County, Va., in third, fourth and fifth place, respectively.

Maryland ranked first in the list of high-income states, with a median household income of $71,122, ahead of New Jersey, Alaska, Connecticut and the District of Columbia.  

Six of the counties in the top 25 are in Maryland, five are in Virginia, four are in New Jersey and three are in New York.

Other Maryland counties in the top 25 are Montgomery (11); Charles (15); Anne Arundel (18); Calvert (19) and St. Mary’s (21).

Economists attributed Howard's prosperity to a variety of factors, including its suburban nature, proximity to federal jobs in Washington, D.C. and strong educational system.

Anirban Basu, an economist at the Baltimore-based Sage Policy Group, called Howard County's ranking "impressive."

"For Howard County to rank second in the country [in median household income] tells us a lot about Howard County and its broadly shared prosperity," he said.

Basu laid out five factors that he thought played the greatest role in Howard County's economic stability:

· Suburban character: "One of the reasons that suburban counties often have higher median household income relative to cities is that cities tend to have at least some degree of concentration of poverty and there's relatively less of that in suburbs."

· Nature of the housing stock: "If one observes the housing stock in Clarksville, Ellicott City or elsewhere, a lot of the housing is single-family residential. And homeowners, on average, tend to have higher incomes than renters."

· Large workforce of federal employees: "Federal workers tend to be highly educated and their compensation reflects, at least in part, their education. Howard County is also the community of choice for people who work for government contractors, including those located in neighboring jurisdictions in Montgomery and Anne Arundel counties."

· Renowned public school system: "Howard County has the reputation of having the finest public schools in Maryland, and Maryland has the reputation of having the finest public schools in America. This status attracts the types of people who are affluent enough that they can choose what kind of community they live in, and they disproportionately select Howard County because it gives them an opportunity to provide their children with the best public education possible."

· Concentration of successful technology companies: "Howard County has established itself as a technological hub… Sometimes these businesses aren't always as obvious as one might expect because they're not the Microsofts, Facebooks or Twitters of the world. In their locations, those businesses are often unnoticeable, [but they're there]."

Taken together, these factors are "working in the same direction and all positioning Howard County to be among the most prosperous in the nation," Basu said.

In 2011, Howard County ranked fifth in median household income among counties nationwide, at $98,953, which would seem to suggest its fortunes took a leap last year.

But Mark Goldstein, an economist for the Maryland Department of Planning, cautioned against reading too much into the rankings of counties within a few places of each other.

Because the American Community Survey is a much smaller survey than the Census, which attempts to collect data on every American citizen, there is a much higher margin of statistical error.

In the case of the 2011 rankings, Howard County actually tied for third with four other counties when margin of error was taken into account. In 2012, it was statistically tied with Fairfax and Hunterdon counties, although Loudoun County still held enough distance to claim first place all for itself.