State Routes in Tennessee were previously separated into secondary and primary routes. The differences were denoted by separate shield styles, with primary routes in rectangles and secondary routes in triangles. The two-tier system was derived from the Federal-Aid Primary and Federal Aid Secondary system of roads. That system was replaced with the National Highway System (NHS) in 1993, as part of the 1991 Intermodal Surface Transportation Efficiency Act (ISTEA). A de facto primary and secondary system still exists today, though the distinction is based upon importance versus funding/maintenance. More on the Tennessee state route system can be found at Bill Burmaster’s web site.
Top County Populations
Top City Populations
Sources: 2020 U.S. Census Data (metro populations and counties), 2020 U.S. Census Estimate (cities)