The western terminus of Loop 168 is at FM 947. The route travels to the east along Wall Street before ending at Loop 157 one block north of that route's intersection with US 59 / US 84.
According to TxDOT, Loop 168 is the shortest numbered route in Texas, with a total length of 0.074 miles (0.119 km), or approximately 391 feet (119 m). However, Spur 200 has a certified length of only 0.050 miles (0.080 km).
When originally designated in 1945, Loop 168 connected with US 59 at both ends; the western terminus was at US 59 / US 84 one block further south, with the route turning along Main Street to an intersection with US 59, and the eastern terminus was at its present location, at the former alignment of US 59 through northeastern Tenaha. In 1950, the western end was moved to its current location, with FM 947, which was commissioned in 1948, being designated over that section of Main Street. In 1983, when US 59 was rerouted to the east, the old route through Tenaha along Center Street was actually designated as Loop 168, and the one-block route along Wall Street was designated as a spur connection. It is unclear as to whether this change was signed, as in 1985, old US 59 had its designation changed to Loop 157, and Loop 168 reverted to its previous routing.