Texas State Highway 21

State Highway 21
State Highway 21
Route information
	Maintained by TxDOT
Length	312.50 mi (502.92 km)
Existed	April 4, 1917–present
Major junctions
West end	I-35 at San Marcos
	US 183 / SH 130 Toll in Mustang Ridge; US 290 in Paige; US 77 near Lincoln; US 190 / SH 6 in Bryan; I-45 / US 190 in Madisonville; US 287 in Crockett; US 69 in Alto; ; Future I-69 / US 59 in Nacogdoches; US 96 in San Augustine;
East end	LA 6 near Milam
Location
Country	United States
State	Texas
Counties	Hays, Caldwell, Bastrop, Lee, Burleson, Brazos, Madison, Houston, Cherokee, Nacogdoches, San Augustine, Sabine
Highway system
	Highways in Texas; Interstate; US; State; Toll; Loops; Spurs; FM/RM; Park; Rec;

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.

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

[State_Highway_21-1] Transportation Planning and Programming Division (n.d.). "State Highway No. 21". Highway Designation Files. Texas Department of Transportation. Retrieved August 30, 2013.

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