Grundy County is located in Middle Tennessee, on the border of East Tennessee. The Cumberland mountains divide the county into a series of valleys and plateaus. The county was formed on January 29, 1844 with lands from Coffee, Franklin & Warren counties.
Grundy County is joined on the West by Coffee and Franklin Counties, on the South by Marion County, on the East by Sequatchie and Van Buren Counties and on the North by Warren County.