The western terminus of RM 1431 is in Llano County, at an intersection with SH 261 along the southwestern shore of Lake Buchanan. The roadway initially travels to the southwest, crossing SH 29, before turning to the south and into Kingsland. After crossing into Burnet County, RM 1431 takes a more southeasterly path through Granite Shoals and Marble Falls, where it crosses US 281. The highway continues east and roughly parallels Lake Travis to its south, crossing into Travis County and through the cities of Lago Vista and Jonestown. RM 1431 then enters Cedar Park in Williamson County, where it has intersections with US 183 and the 183A Toll Road at the current end of that route's tolled segment. The roadway heads east into Round Rock, Texas, where it reaches its eastern terminus at Interstate 35's Exit #256. While state maintenance ends here, the roadway continues into Round Rock as University Boulevard and ends in Taylor as Chandler Road.
History
FM 1431 was originally designated in Starr County on July 15, 1949, on a route from FM 755 eastward to La Reforma at the Starr-Hidalgo County line. That designation was canceled on November 30, 1949 and the route was combined with FM 1017. 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 miles to the east. The designation was changed to RM 1431 on October 1, 1956. The route was extended westward into Llano County and to SH 29 on November 21, 1956, and further eastward to US 183 in White Stone on October 31, 1958, replacing RM 1328 which started at Travis Peak Road. RM 1431 was extended to its current western terminus at SH 261 on September 5, 1973, and to its current eastern terminus at Interstate 35 on June 21, 1978. Officially, a segment of the route along Whitestone Blvd. in Cedar Park was transferred to the jurisdiction of the city on January 28, 2010.
Business route
RM 1431 has one auxiliary route, Business FM 1431-J, designated along a former alignment of RM 1431 in Burnet County east of Marble Falls. The business route was created in 2010 and serves the Waterford subdivision and golf club on Lake Travis. The road is named as a Farm to Marketbusiness route even though its parent route is a Ranch to Market Road, although the distinction is inconsequential since the words Farm and Ranch are replaced with Business on business route shields. The route was created when RM 1431 was aligned along a more direct path from west to east bypassing the business route's more southerly dip. The business route intersects no other numbered state highways between its termini with RM 1431.
