[1] At first, I-540 was a short spur connecting Fort Smith and Van Buren to I-40 as one of the original five Arkansas Interstates.

[2] The route ran 14.7 miles (23.7 km) to the Oklahoma state line to I-40 in Van Buren.

The older portion of I-540, completed in the 1970s, connects I-40 southward to the Oklahoma state line, going through Van Buren and Fort Smith.

This particular spur starts at exit 7 on I-40 (being seven miles (11 km) east of the state line with Oklahoma).

The remainder, for a grand total of approximately 15 miles (24 km), travels through Fort Smith.

The first exit along this segment of I-540/US 71 is with US 64 and U.S. Highway 71 Business (US 71B), which leads west into the Van Buren Historic District and east to Alma.

Continuing south, I-540/US 71 passes over Highway 162 (AR 162, Kibler Road), with no access between the routes.

Originally, the AHTD asked the American Association of State Highway and Transportation Officials (AASHTO), who are in charge of Interstate and U.S. Highway route numbering, to allow the Interstate segment between Fort Smith and Bentonville to be named I-49 in order to emphasize plans to extend the route from Shreveport, Louisiana, through Arkansas to Kansas City, Missouri.