[1] The western terminus of RM 1431 is in Llano County, at an intersection with SH 261 along the southwestern shore of Lake Buchanan.

[5][6] RM 1431 then enters Cedar Park in Williamson County,[5] where it has intersections with US 183, the 183A Toll Road, and FM 734 (Parmer Lane).

[1] The current route was first designated on May 23, 1951, as FM 1431, and ran from US 281 in Marble Falls to the community of Smithwick approximately 11.3 miles (18.2 km) to the east.

It was extended eastward to Travis Peak Road on October 31, 1958, and further east to US 183 in White Stone (now part of Cedar Park) on November 26, 1958, replacing RM 1328.

Officially, a 1.1-mile (1.8 km) segment of the route along Whitestone Boulevard in Cedar Park was transferred to the jurisdiction of the city on January 28, 2010.