Union Parish is a parish located in the north central section of the U.S. state of Louisiana. As of the 2020 census, the population was 21,107. The parish seat is Farmerville. The parish was created on March 13, 1839, from a section of Ouachita Parish. Its boundaries have changed four times since then.

U.S. Route 167 is a north-south United States Highway within the U.S. states of Louisiana and Arkansas. It runs for 500 miles (800 km) from Ash Flat, Arkansas at U.S. Route 62/U.S. Route 412 to Abbeville, Louisiana at Louisiana Highway 14. It goes through the cities of Little Rock, Arkansas, Alexandria, Louisiana, and Lafayette, Louisiana.