Based on the latest annual population estimates for July 1, 2013, Williamson County is the fastest growing county in Tennessee in 2013, ranking 56th in the nation (out of 3,143 counties) and growing 3.1 percent since 2012. Williamson was followed by Rutherford County at 2.5 percent, ranking 93rd in the nation. Since 2010, Williamson County has grown 8.1 percent, well above the state's average of 2.2 percent.
Davidson County added the largest number of people in the state from 2012 to 2013, with an additional 9,801 people (representing 1.5 percent growth). Rutherford County grew by 6,925 people, and Williamson by 5,904 people. These three middle Tennessee counties, alone, accounted for 55 percent of the state's population increase from 2012 to 2013. During this time period, 44 Tennessee counties experienced declines in their populations. Montgomery County lost 1,082 people from 2012 to 2013. However, since 2010, Montgomery County has experienced strong population growth of 6.2 percent.
While experiencing a slight decline in population since 2012, Shelby County remains the most populous county in Tennessee, with 939,465 residents, followed by Davidson County (658,602) and Knox County (444,622).
See the Population Estimates webpage for detailed tables of all counties in the nation including components of change.