Tenn. Code Ann. § 41-22-301

The county mayor, county clerk and sheriff of each county are constituted a board for their respective counties, whose duty it is to enter into contracts with public road commissioners or other officers or road contractors having the superintendence of working the public roads, for the employment on the public roads of inmates confined in the county jails for the nonpayment of fines and/or costs adjudged against them by the courts.