Per-capita personal income on Long Island grew an average of 3 percent last year compared with 2010, according to data released Monday.
The federal Bureau of Economic Analysis estimated the typical Nassau County resident earned $67,776 in 2011, an increase of $2,111 over the previous year.
The typical Suffolk County resident had income of $52,350 last year, up $1,640 from 2010.
Among the nation's 3,113 counties, the top earners lived in Manhattan, where income averaged $121,301 last year, the bureau said. The lowest per-capita income was $16,752 in Crowley County, Co.
Per-capita personal income nationwide was $41,560 in 2011. Only 20 percent of all counties exceeded this number.
In New York State, personal income averaged $51,126. Of the state's 62 counties, Nassau placed third in per-capita income behind Manhattan and Westchester County. Suffolk was No. 6 after Rockland and Putnam.
Separately, the bureau said rising incomes nationally were due to increases in wages (5.5 percent, year over year) and in dividends, interest and other investment income (7.6 percent).
Some experts said the income data is closely followed because it's the only comprehensive annual measure of economic activity in the counties.