According to information from the US Census Bureau, Rutherford County's population as of April 1, 2020, is 341,486. That is up 78,882 people from the 2010 census.

Of the largest five counties in Tennessee, Rutherford County has the greatest growth rate (30.03%). Davidson County is second with 14.23% followed by Knox with 10.81% and Hamiltion with 8.84% respectively. Williamson County, No. 6 is size, had growth of 35% to a population of 247,726.

Middle Tennessee counties accounted for the greatest area of growth in Tennessee. Middle Tennessee counties rankings are:

2. Davidson

5. Rutherford

6. Williamson

7. Montgomery

8. Sumner

10. Wilson

14. Maury

17. Putman

19. Robertson

24. Coffee