Karnes City is a city in and county seat of Karnes County, Texas, United States. The population was 3,111 at the 2020 census, up from 3,042 at the 2010 census. The town was named after Henry Karnes of the Texas Revolution. Karnes is 24 miles (39 km) southeast of Floresville and 54 miles (87 km) southeast of San Antonio on U.S. Highway 181.

In 1894, as a result of a special election, the county seat was moved from Helena to Karnes City. Ten years earlier, Colonel William G. Butler (1831–1912) had blamed Helena and its corrupt mayor for the death of his son, Emmett, who was killed on December 26, 1884, by a stray bullet from a bar fight. Butler, a wealthy rancher, retaliated by arranging for the San Antonio and Aransas Pass Railway, which started construction in 1885, to bypass Helena.

The railway started operation in 1886. By 1890, with no rail line, Helena was at a disadvantage for serving the county's needs. In 1890, a group of businessmen purchased land on the rail line, 7 miles (11 km) southwest of Helena, with the specific intent of building a new town to serve as the county seat. The new town, named for Colonel Henry Wax Karnes (1812–1840), veteran of the Texas Revolution and a leader of the Texas Rangers, was a viable settlement by 1894, when the county voted to move its seat from Helena. Karnes City continued to grow, while Helena faded into a ghost town.

The story was fictionalized in the 1969 episode "The Oldest Law" of the television series Death Valley Days. In the episode, Jim Davis played the role of Colonel Butler, while Stacy Harris played Helena's mayor.

Karnes City is located in central Karnes County at 28°53′N 97°54′W / 28.883°N 97.900°W / 28.883; -97.900 (28.8882, –97.9013). According to the United States Census Bureau, the city has a total area of 2.1 square miles (5.5 km), of which 0.03 square miles (0.08 km), or 1.37%, are water.

U.S. 181 runs through the southwest side of Karnes City, leading northwest 54 miles (87 km) to San Antonio and south 37 miles (60 km) to Beeville. Texas State Highway 123 runs north from Karnes City 25 miles (40 km) to Stockdale, and State Highway 80 leads northeast 19 miles (31 km) to Gillett.

Historical population

Census	Pop.	Note	%±
1920	787		—
1930	1,141		45.0%
1940	1,571		37.7%
1950	2,588		64.7%
1960	2,693		4.1%
1970	2,926		8.7%
1980	3,296		12.6%
1990	2,916		−11.5%
2000	3,457		18.6%
2010	3,042		−12.0%
2020	3,111		2.3%
U.S. Decennial Census

Karnes City racial composition as of 2020
(NH = Non-Hispanic)

Race	Number	Percentage
White (NH)	903	29.03%
Black or African American (NH)	87	2.8%
Native American or Alaska Native (NH)	16	0.51%
Asian (NH)	10	0.32%
Some Other Race (NH)	2	0.06%
Mixed/Multi-Racial (NH)	53	1.7%
Hispanic or Latino	2,040	65.57%
Total	3,111

As of the 2020 United States census, there were 3,111 people, 657 households, and 486 families residing in the city.

As of the census of 2000, there were 3,457 people, 1,007 households, and 720 families living in the city. The population density was 1,627.6 inhabitants per square mile (628.4/km). There were 1,180 housing units at an average density of 555.6 per square mile (214.5/km).

There were 1,007 households, out of which 35.8% had children under the age of 18 living with them, 46.7% were married couples living together, 19.3% had a female householder with no husband present, and 28.5% were non-families. 25.2% of all households were made up of individuals, and 14.8% had someone living alone who was 65 years of age or older. The average household size was 2.81 and the average family size was 3.37.

In the city, the population was spread out, with 25.9% under the age of 18, 11.5% from 18 to 24, 31.1% from 25 to 44, 16.6% from 45 to 64, and 14.9% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 122.7 males. For every 100 females age 18 and over, there were 130.6 males.

The median income for a household in the city was $25,156, and the median income for a family was $27,206. Males had a median income of $30,446 versus $18,261 for females. The per capita income for the city was $12,243. About 23.1% of families and 27.0% of the population were below the poverty line, including 36.6% of those under age 18 and 22.6% of those age 65 or over.

Karnes City is served by the Karnes City Independent School District: Karnes City Primary, Roger E. Sides Elementary School, Karnes City Junior High School, and Karnes City High School.

The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen climate classification system, Karnes City has a humid subtropical climate, Cfa on climate maps.

• Maria Moreno, farmworker and labor organizer
• [[ Matt Carnes- left when the town changed over to a K.

• Official website