PR 12 begins at an at-grade intersection with FM 1155 just outside the border of the State Historic Site.

The road proceeds eastward for a short distance before bending northeastward.

The roadway continues northeast through dense trees before reaching its northern terminus, an at-grade intersection with a small park road.

[3][4] Park Road 12 was first designated on September 26, 1939, as a redesignation of State Highway 229.

This decision was approved on October 15 of the same year, and removed approximately 0.6 miles (0.97 km) from the route.