Tennessee State Route 840 (SR 840), also designated as Tennessee National Guard Parkway, is a state highway around Nashville, Tennessee, built and directed by the Tennessee Department of Transportation (TDOT). First proposed by former Governor Lamar Alexander as part of a system of Bicentennial Parkways, construction began in 1991 and was completed in 2012. The roadway is 77.28 miles (124.37 km) long, and it serves the cities of Lebanon, Murfreesboro, Franklin, and Dickson.