Texas State Highway 21 has one named section in Brazos County:
- San Jacinto Lane from Sandy Point Road (FM 1687) and William J. Bryan Parkway (FM 158) northeast to Texas Avenue (BS-6) in Bryan
TX-21 enters from Burleson County (overlapped by FM 50 for the first mile) without a local name and heads east to Sandy Point Road and William J. Bryan Parkway. After going through downtown Bryan, TX-21 continues northeast without a local name from Texas Avenue to Madison County. TX-21 is overlapped by US-190 from Earl Rudder Freeway (TX-6) northeast; US-190 also overlaps TX-6 going northwest. TX-21 has a business route running through Kurten, with the main road following a bypass highway to the southeast of town.
Junction List[]
Between Burleson County and Sandy Point/William J. Bryan
| Location | Mile | Roads intersected | Notes |
|---|---|---|---|
| 1.1 | FM 50 | No stopsign, east end of FM 50 overlap (overlap continues west into Burleson County) | |
| 2.7 | Old San Antonio Road (OSR) | No stopsign | |
| 5.1 | TX-47 | Interchange, accessible only from west | |
| Bryan | 9.1 | Harvey Mitchell Parkway (FM 2818) | Interchange, stoplight and stopsign |
| 10.3 | Sandy Point Road (FM 1687)/William J. Bryan Parkway (FM 158)/San Jacinto Lane (TX-21) | Stoplight, becomes San Jacinto Lane to the northeast |
Between Texas Avenue and Madison County
| Location | Mile | Roads intersected | Notes |
|---|---|---|---|
| Bryan | 0 | Texas Avenue (BS-6) | Stoplight |
| 0.3 | Tabor Road (FM 974) | No stopsign | |
| 1.0 | Earl Rudder Freeway (TX-6)/US-190 | Interchange, stoplights, west end of US-190 overlap (US-190 also overlaps Earl Rudder Freeway (TX-6) to the northwest) | |
| 2.4 | Marino Road | Flashing yellow light | |
| Wixon Valley | 5.8 | FM 2776/Andert Road | Flashing yellow light |
| Kurten | 8.7 | BS-21 | No stopsign |
| 9.1 | FM 2038 | No stopsign | |
| 10.0 | BS-21/Democrat Road | No stopsign | |
| 15.2 | Tabor Road (FM 974) | No stopsign | |
| 16.7 | Madison County | TX-21 continues northeast into Madison County |