Washington Routt County has topped 20,000 people, according to the latest figures from the Census Bureau.
The county grew by 2.9 percent from April 1, 2000 to July 1, 2001, according to estimates released Monday. The new population is 20,255 people, an increase of 565 residents since the official count in the 2000 Census.
Routt County's rate of growth tied it with Summit County for 18th in the state of Colorado. Summit added 6,777 residents and its population is now 24,225. Among other ski resort counties, Eagle County grew 3.3 percent to 43,027 residents, while Pitkin County's population fell some 62 residents to 14,810.
Moffat County's population was estimated at 13,154, a decline of some 30 residents. In all, there were 25 Colorado counties that lost population in the Census estimates.
Among other area counties, Grand County saw a 2.2-percent increase to 12,711 residents, and Rio Blanco County's population fell to 5,945.
Overall, Colorado added 116,453 residents, an increase of 2.7 percent to 4.41 million residents.
The fastest-growing county in Colorado and the nation was Douglas County south of Denver. Douglas County grew 13.6 percent over a 15-month period.
The other counties in the top 10 in Colorado in terms of percentage growth include Elbert, 7.9 percent; Weld, 7.7; Archuleta, 7.7; Park, 7.3; Custer, 5.4; San Miguel, 5.4; Saguache, 5.2; San Juan, 5.0; and Teller, 4.2.
Overall, the West is the nation's fastest-growing region.
The bureau reported population increases in 55 percent of the 3,141 counties in the United States, according to estimates made for April 1, 2000, to July 1, 2001.
The Washington suburb of Loudoun, County, Va., had the second-largest growth at 12.6 percent, followed by the Atlanta suburb of Forsyth County, Ga., at 12.1 percent.
The only Northern city in the top 10 was Scott County, Minn., outside Minneapolis. It grew 9.9 percent.
Maricopa, Ariz., had the largest population increase of any county, growing by 122,649 people. That represented a 4-percent increase, bringing its population to 3.19 million.
The nation's largest county, Los Angeles County, grew by 118,156 people, a 1.2-percent increase that brought is population up to 9.64 million.
Loving County, Texas, is the least populous county, with fewer than 100 residents as of July 1.
The estimates are taken from 2000 Census Bureau data that has been adjusted based upon estimates for births, deaths and migration.