Rutherford County is a county located in the U.S. state of Tennessee. It is located in Middle Tennessee. As of the 2010 census, the population was 262,604, growing to an estimated 332,285 in 2019, making it the fifth-most populous county in Tennessee. A study conducted by the University of Tennessee projects Rutherford County to become the third largest county in Tennessee by population by 2050. Its county seat is Murfreesboro, which is also the geographic center of Tennessee. As of 2010, it is the center of population of Tennessee.