State Route 840 is a state highway

State highway

State highway, state road or state route can refer to one of three related concepts, two of them related to a state or provincial government in a country that is divided into states or provinces :#A...

, a limited-access expressway being built around Nashville, Tennessee

Nashville, Tennessee

Nashville is the capital of the U.S. state of Tennessee and the county seat of Davidson County. It is located on the Cumberland River in Davidson County, in the north-central part of the state. The city is a center for the health care, publishing, banking and transportation industries, and is home...

, and directed by the Tennessee Department of Transportation

Tennessee Department of Transportation

The Tennessee Department of Transportation is a multimodal agency with statewide responsibilities in aviation, public transit, waterways and railroads...

. First proposed by former Governor Lamar Alexander

Lamar Alexander

Andrew Lamar Alexander is the senior United States Senator from Tennessee and Conference Chair of the Republican Party. He was previously the 45th Governor of Tennessee from 1979 to 1987, United States Secretary of Education from 1991 to 1993 under President George H. W...

 as part of a system of "Bicentennial Parkways", construction began on this expressway in 1991 - on the first segment extending south from Interstate 40

Interstate 40

Interstate 40 is the third-longest major east–west Interstate Highway in the United States, after I-90 and I-80. Its western end is at Interstate 15 in Barstow, California; its eastern end is at a concurrency of U.S. Route 117 and North Carolina Highway 132 in Wilmington, North Carolina...

 at Lebanon

Lebanon, Tennessee

Lebanon is a city in Wilson County, Tennessee, in the United States. The population was 20,235 at the 2000 census. It serves as the county seat of Wilson County. Lebanon is located in middle Tennessee, approximately 25 miles east of downtown Nashville. Local residents have also called it...

. The roadway currently serves the cities of Lebanon, Murfreesboro, and Franklin.