Monteagle is a town in Franklin, Grundy, and Marion counties in the U.S. state of Tennessee, in the Cumberland Plateau region of the southeastern part of the state. The population was 1,238 at the 2000 census – 804 of the town's 1,238 residents lived in Grundy County, 428 in Marion County, and 6 in Franklin County. The population at the 2020 census was 1,3…Monteagle is a town in Franklin, Grundy, and Marion counties in the U.S. state of Tennessee, in the Cumberland Plateau region of the southeastern part of the state. The population was 1,238 at the 2000 census – 804 of the town's 1,238 residents lived in Grundy County, 428 in Marion County, and 6 in Franklin County. The population at the 2020 census was 1,393.