Hays County is located in south-central Texas, on the border between the Edwards Plateau and the southern Black Prairie region. It covers an area of 693.5 square miles and its county center is 98°00' west longitude and 30°00' north latitude, twenty-three miles southwest of Austin. The county is named after John Coffee Hays, a Texas park ranger and Mexican-American war officer. Hays County has been inhabited for thousands of years, with evidence of Paleo-Indians found in the region dating back to 6000 BC.
Archaeological evidence of native agriculture dates back to 1200 AD. The county's population was distributed as 24.50% under the age of 18, 20.50% from 18 to 24, 28.20% from 25 to 44, 19.10% from 45 to 64, and 7.70% from 65 years of age or older. The median age was 28 years. For every 100 females, there were 101.30 males; for every 100 females age 18 and over, there were 99.50 males. Democratic voters primarily reside along the I-35 Corridor and the communities of San Marcos, home of Texas State University, and the city of Kyle generally vote for Democrats.
Buda, Dripping Springs and Wimberley generally vote for Republicans. The Balcones escarpment divides Hays County into mountainous, tree-covered ranches in three-quarters of the northwest and grassy agricultural plains in the southeastern quarter. The main natural grasses are the large blue stalk and indigenous grass; the trees commonly associated with Central Texas, including live oak, cedar, walnut and mesquite, are native to Hays County. The elevation rises from east to west, ranging from 600 to over 1,400 feet. The county's many streams generally flow in an eastward direction; the main waterways are the Bear, Cypress and Onion streams and the Blanco and San Marcos rivers. The Edwards aquifer is located below the east, where San Marcos Springs, the second largest in Texas, produces about 160 cubic feet per second.
The soil ranges from fine limestone to black, waxy, chocolate and gray marl. The average annual rainfall is 33.75 inches; the average maximum temperature in July is 96° F; the average minimum temperature in January is 40° F; Hays County has a 254-day growing season. On March 1, 1848, the state legislature formed Hays County from the territory that was formerly part of Travis County. Southwest Texas Normal School was authorized at the turn of the century and opened in 1903 as a teacher training institution; it became Southwest Texas State University in 1969. In 1880, the first Hays County railroad was completed to San Marcos from Austin; it was later extended to San Antonio. Since the turn of the century, Hays County has enjoyed a steady influx of tourists attracted by the caves, springs and spas of Wimberley and San Marcos. In 1691, Domingo Terán de los Ríos crossed the southern tip of the county on his way to the East Texas missions and the Red River.
The boundaries remained stable for nearly a century until 1955 when more than 16,000 acres were added to Hays County. Although Democrat Jimmy Carter managed to win a majority there in 1976, Republican presidential candidates won Hays County in nearly every election from 1980 to 2004.
