Texas State Highway 21

State Highway 21 marker
State Highway 21
Map
Route information
Maintained by TxDOT
Length312.50 mi[1] (502.92 km)
ExistedApril 4, 1917–present
Major junctions
West end I-35 at San Marcos
Major intersections
East end LA 6 near Milam
Location
CountryUnited States
StateTexas
CountiesHays, Caldwell, Bastrop, Lee, Burleson, Brazos, Madison, Houston, Cherokee, Nacogdoches, San Augustine, Sabine
Highway system
SH 20 SH 22

State Highway 21 (SH 21) runs from the Texas-Louisiana boundary east of San Augustine to San Marcos in east and central Texas. SH 21 mostly follows the alignment of the Old San Antonio Road and the El Camino Real, except for the portion between Midway and Bryan, where the Old San Antonio Road took a more northerly route, and SH 21 follows a more direct route. That section of the Old San Antonio Road is served by Texas State Highway OSR.

  1. ^ Transportation Planning and Programming Division (n.d.). "State Highway No. 21". Highway Designation Files. Texas Department of Transportation. Retrieved August 30, 2013.