# Texas State Highway 123

State Highway 123 (SH 123) is a north–south state highway in Texas, United States, that connects U.S Route 181 (US 181) in Karnes City with Interstate 35 (I-35) in San Marcos. The route was initially proposed in 1927 and has had minimal changes to its routing since then.

## Route description

SH 123 begins at an intersection with US 181 just south of Karnes City and proceeds northward along the town's eastern edge. The route intersects the Business Route of US 181 and Texas State Highway 80 as it passes through town. The road continues north through farmlands before reaching an intersection with US Route 87 in Stockdale. The route continues north through ranchlands until Seguin. Reaching Seguin, Texas State Highway 46 begins, peeling off to the northwest toward New Braunfels. SH 123 continues around the eastern edge of Seguin, where it is known locally as "the Bypass", and there it intersects US 90 Alternate, US 90, and Interstate 10. The highway continues north, reaching its northern terminus at Interstate 35 in San Marcos.

## History

The route was initially proposed on April 12, 1927 from Stockdale to San Marcos with a proposed extension south to Karnes City. On September 21, 1931, it was rerouted to end in Floresville. On August 4, 1932, it was restored to Karnes City, and the old route was renumbered as SH 168. On November 6, 1934, it was rerouted to Yorktown. On February 16, 1935, its south end was changed back to Karnes City. On November 18, 1938, SH 123 Loop was designated in Karnes City. On September 26, 1939, SH 123 Loop was renumbered as Loop 17. Paving was completed in the mid-1940s.

## Major intersections

| County | Location | mi | km | Destinations | Notes |
| Karnes | ​ | 0.0 | 0.0 | US 181 / Bus. US 181 ends / SH 80 ends – Kenedy, Corpus Christi, San Antonio | Southern terminus: southern end of US 181 Bus. / SH 80 concurrency |
| Karnes | Karnes City | 1.4 | 2.3 | Bus. US 181 north | Northern end of US 181 Bus. concurrency |
| Karnes | Karnes City | 1.9 | 3.1 | SH 80 north – Helena, Gillett | Northern end of SH 80 concurrency |
| Karnes | ​ | 2.5 | 4.0 | Bus. SH 123 south – Karnes City | |
| Karnes | ​ | 6.3 | 10.1 | FM 81 east – Panna Maria | Southern end of FM 81 concurrency |
| Karnes | ​ | 6.5 | 10.5 | FM 81 west – Hobson | Northern end of FM 81 concurrency |
| Karnes | Pawelekville | 13.4 | 21.6 | FM 887 – Falls City, Gillett | |
| Wilson | ​ | 17.4 | 28.0 | FM 541 west – Kosciusko, Poth | |
| Wilson | ​ | 20.9 | 33.6 | FM 1347 – Kosciusko, Denhawken | |
| Wilson | ​ | 23.9 | 38.5 | FM 537 west – Floresville | |
| Wilson | Stockdale | 25.4– 25.5 | 40.9– 41.0 | US 87 / SH 97 to SH 119 – Floresville, San Antonio, Nixon | interchange |
| Wilson | Stockdale | 26.3 | 42.3 | Bus. US 87 (Main Street) – Stockdale Business District, Pandora, Nixon | |
| Wilson | ​ | 28.6 | 46.0 | FM 3335 east to FM 1107 | |
| Wilson | ​ | 35.9 | 57.8 | FM 1681 east – Nixon | |
| Guadalupe | ​ | 45.6 | 73.4 | FM 477 east | |
| Guadalupe | Seguin | 46.4 | 74.7 | SH 46 north / Bus. SH 123 north – Seguin, New Braunfels | |
| Guadalupe | Seguin | 49.3 | 79.3 | FM 466 (Eastwood Drive) to SH 80 – Seguin | |
| Guadalupe | Seguin | 49.7 | 80.0 | US 90 Alt. (Court Street) – Seguin, Gonzales, Texas Lutheran University, Sebastopol Historical Park | |
| Guadalupe | Seguin | 50.9 | 81.9 | US 90 – Seguin, Luling | |
| Guadalupe | Seguin | 51.9– 52.0 | 83.5– 83.7 | I-10 – San Antonio, Houston | I-10 exit 610 |
| Guadalupe | Seguin | 53.5 | 86.1 | Bus. SH 123 south – Seguin | |
| Guadalupe | Seguin | 53.7 | 86.4 | FM 20 east – Fentress | |
| Guadalupe | Geronimo | 57.3 | 92.2 | FM 2623 east – Fentress | |
| Guadalupe | ​ | 59.4 | 95.6 | FM 758 west – Barbarosa, New Braunfels Municipal Airport, Central Texas Technology Center | |
| Guadalupe | ​ | 60.4 | 97.2 | FM 1339 east – Staples | |
| Guadalupe | Zorn | 62.2 | 100.1 | FM 1101 west – New Braunfels | |
| Guadalupe | ​ | 64.5 | 103.8 | FM 1979 east – Martindale | |
| Guadalupe | ​ | 66.1 | 106.4 | FM 1978 east – Redwood | |
| Hays | San Marcos | 68.5– 68.6 | 110.2– 110.4 | FM 110 west | |
| Hays | San Marcos | 69.6 | 112.0 | RM 12 north (Wonderworld Drive) | |
| Hays | San Marcos | 70.9 | 114.1 | FM 621 east – Staples State Fish Hatchery | |
| Hays | San Marcos | 71.1– 71.2 | 114.4– 114.6 | I-35 / Loop 82 – San Antonio, Austin | Northern terminus |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus ||||||

## Business routes

The route has two business segments: Business 123-B (largely on Austin Street) through historic downtown Seguin and Business 123-D in Karnes City.