In 1924, the
Texas Legislature directed the State Parks Board, a predecessor agency to the
Texas Parks and Wildlife Department, to consider establishing a major destination park within the
Davis Mountains. After the parks board failed to receive appropriations or donated land for a new park, the Legislature then instructed the State Highway Department, which preceded the
Texas Department of Transportation (TxDOT), to build a Davis Mountains State Park Highway in 1927. Landowners finally agreed to donate land for the park in 1933 to boost the local economy devastated by the
Great Depression. With the creation of the park, a state park highway was no longer necessary, and that highway initially became
SH 166. Construction of PR 3 began in 1933 soon after the establishment of the state park. Like the park, the road was originally constructed by the Civilian Conservation Corps. The road at this time consisted of the main route between the park entrance and Indian Lodge. On September 22, 1936, the state highway commission initiated an investigation at the request of the state's parks board into the incorporation of certain park roads as part of the state highway system after which the highway commission would assume maintenance of these roads. The highway commission accepted the park road in Davis Mountains State Park and seven other parks as the original park roads in the state system on June 22, 1937. The state ended the SH 166 designation over that same portion in 1941. ==Major intersections==