State Highway 123 is a north–south state highway that runs from Interstate 35 in San Marcos

San Marcos, Texas

San Marcos is a city in the U.S. state of Texas, and is the seat of Hays County. Located within the metropolitan area, the city is located on the Interstate 35 corridor—between Austin and San Antonio....

 to US 181 in Karnes City

Karnes City, Texas

Karnes City is a city in Karnes County, Texas, United States. The population was 3,457 at the 2000 census. It is the county seat of Karnes County. The town was named after Henry Karnes of the Texas Revolution. Karnes is some twenty-five miles south of Floresville on U.S...

. The route was initially proposed in 1928 and has had minimal changes to its routing since then.

Route description

SH 123 begins at an intersection with US Route 181 just south of Karnes City and proceeds nothward along the eastern edge of the town. The route intersects the Business Route of US 181 and Texas State Highway 80 as it passes through town. The routes continues northward through farmlands before reaching an intersection with US Route 87 in Stockdale. The route continues northward to reach Seguin. In Seguin, the route continues around the eastern edge of the city, intersecting Texas State Highway 46, US Route 90 and US 90 Alternate, and Interstate 10

Interstate 10

Interstate 10 is the fourth-longest Interstate Highway in the United States, after I-90, I-80, and I-40. It is the southernmost east–west, coast-to-coast Interstate Highway, although I-4 and I-8 are further south. It stretches from the Pacific Ocean at State Route 1 in Santa Monica,...

. The road continues north, reaching its northern terminus at Interstate 35

Interstate 35

Interstate 35 is a north–south Interstate Highway in the central United States. I-35 stretches from Laredo, Texas, on the U.S.-Mexico border to Duluth, Minnesota, at Minnesota Highway 61 and 26th Avenue East. Many interstates used to have splits or spurs indicated with suffixed letters , but I-35...

 on the south side of San Marcos.

The route has two business segments: Business 123-B through Seguin, and Business 123-D in Karnes City.

Route history

The route was initially proposed in 1928 from Stockdale to San Marcos with a proposed extension south to Karnes City. By 1940 the southern extension was completed, but was still unpaved. Paving was completed in the mid 1940s.

Intersecting Highways