According to the United States Census Bureau, Flagler County, Florida, which is located along the Atlantic coast between Daytona Beach and Jacksonville, was the nation’s fastest-growing county between July 1, 2003, and July 1, 2004. The county experienced a 10.1 percent population increase, growing from 62,696 to 69,005 people in just one year.
Florida led all states with 14 of the nation’s 100 fastest-growing counties. St. Johns, Florida, which borders Flagler to the north, the second Florida county on the list and was the ninth fastest-growing county between 2003 and 2004. See the table below for the ten fastest growing counties by percent increase.
Numerical Increase
The largest numerical gainer in the 2003-2004 period was Maricopa County (Phoenix), Arizona, which added 112,233 new residents to its county's population. Maricopa County was followed by Riverside County (California) in second place with 89,128 more people in one year, Los Angeles County in third with a 77,357 increase, and Clark County (Nevada) in fourth with 75,285 more people in numerical growth.
Rounding out the top ten are: 5) San Bernardino Co. (California), 6) Harris Co. (Texas), 7) Tarrant Co. (Texas), 8) Palm Beach Co. (Florida), 9) Collin Co. (Texas), and 10) Will Co. (Illinois).
Los Angeles County continued to be the most populous county in the nation, with an estimated 9,937,739 million residents on July 1, 2004.
10 Fastest Growing Counties by Percent Change
| # | County | Increase |
| 1 | Flagler Co., FL | 10.1% |
| 2 | Kendall Co., IL | 8.3% |
| 3 | Loudoun Co., VA | 8.1% |
| 4 | Hanson Co., SD | 7.9% |
| 5 | Lincoln Co., SD | 7.5% |
| 6 | Lampasas Co., TX | 7.3% |
| 7 | Lyon Co., NV | 7.2% |
| 8 | Camden Co., NC | 7.2% |
| 9 | St. Johns Co., FL | 6.7% |
| 10 | Dallas Co., IA | 6.6% |
