State Route 159 is a west to east highway in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Tennessee

Tennessee

Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...

 that is 12 miles (20 km) long. It begins in Carter County

Carter County, Tennessee

Carter County is a county located in the U.S. state of Tennessee. As of 2010, the population was 57,424. Its county seat is Elizabethton.Carter County is part of the Johnson City Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined...

 at State Route 67 and ends in Johnson County at the North Carolina

North Carolina

North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...

 state line. State Route 159 is little-known by the general public by this designation as it is overlain by U.S. Route 321

U.S. Route 321

U.S. Route 321 is a spur of U.S. Route 21. It runs for 526 miles from South Carolina to Tennessee. The northern terminus of U.S. 321 is between Lenoir City and Oak Ridge, Tennessee, at Interstate 40 exit 364, which is about 4 miles west of Interstate 40's junction with Interstate 75...

; the "159" designation is seen on mileposts.

Counties traversed (west to east)

State Route 159 traverses the counties shown in the table below.

Counties traversed by State Route 159
County	miles	kilometers
Carter Carter County, Tennessee Carter County is a county located in the U.S. state of Tennessee. As of 2010, the population was 57,424. Its county seat is Elizabethton.Carter County is part of the Johnson City Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined...	8.5	13.6
Johnson	4.0	6.4