Wake County expanded by 38,841 people in the past year, adding more residents than all but six other counties in the nation, according to census estimates released today.

The county's population rose to 832,970 as of July 2007, the Census Bureau said in a new report. The population grew by 4.9 percent for the period of July 2006 to July 2007.

Wake remains on pace to eventually become the state's largest county. Over the past seven years, Wake added 205,124 residents, a 33 percent increase.

Mecklenburg County for now remained the largest in North Carolina, with a population of 867,067, up 3.8 percent for the year. Mecklenburg ranked 10th in the nation for the number of people added to its population.

North Carolina's population reached 9,061,032, up 2.2 percent.

The census report ranked counties by their growth rates from mid-2000 to mid-2007. For that period, Wake County was the 64th fastest-growing among all counties in the nation with populations of at least 10,000.

Four other North Carolina counties also made the list of the nation's fastest-growing: Johnston in the Triangle (89th fastest growing), Mecklenburg's neighbor of Union (14th) and the coastal counties of Brunswick and Currituck (38th and 72nd respectively).

Here are populations and growth rates for Triangle counties from 2000 to 2007.

Durham: 256,500, 14.9 percent (2.5 percent in one year)

Orange: 124,313, 7.6 percent (1.8 percent in one year)

Chatham: 61,455, 24.6 percent (2.7 percent in one year)

Johnston: 157,437, 29.2 percent (4.3 percent in one year)

Wake: 832,970, 32.7 percent (4.9 percent in one year)

Triangle total: 1.4 million, 34 percent (4 percent in one year)