Petrolia is a city in Clay County, Texas, United States. It is part of the Wichita Falls, Texas metropolitan statistical area. Its population was 514 at the 2020 census, down from 686 at the 2010 census.
Petrolia is located in northern Clay County. Texas State Highway 79 passes through the center of town, leading southwest to Wichita Falls and northeast to Waurika, Oklahoma. Texas State Highway 148 leads south from the center of Petrolia to Henrietta, the Clay County seat.
According to the United States Census Bureau, Petrolia has a total area of , all land.
As of the 2020 census, Petrolia had a population of 514.
The median age was 41.3 years, with 23.2% of residents under 18 and 18.5% 65 or older. For every 100 females there were 83.6 males, and for every 100 females age 18 and over there were 83.7 males age 18 and over.
0.0% of residents lived in urban areas, while 100.0% lived in rural areas.
There were 218 households in Petrolia, of which 27.1% had children under the age of 18 living in them. Of all households, 40.8% were married-couple households, 20.6% were households with a male householder and no spouse or partner present, and 28.4% were households with a female householder and no spouse or partner present. About 27.5% of all households were made up of individuals and 16.9% had someone living alone who was 65 years of age or older.
There were 268 housing units, of which 18.7% were vacant. The homeowner vacancy rate was 5.2% and the rental vacancy rate was 10.0%.
As of the census of 2000, 782 people, 305 households, and 215 families resided in the city. The population density was . The 338 housing units had an average density of . The racial makeup of the city was 94.88% White, 0.77% African American, 1.41% Native American, 1.15% from other races, and 1.79% from two or more races. Hispanics or Latinos of any race were 3.96% of the population.
Of the 305 households, 32.1% had children under 18 living with them, 53.8% were married couples living together, 13.1% had a female householder with no husband present, and 29.2% were not families. About 26.6% of all households were made up of individuals, and 13.8% had someone living alone who was 65 or older. The average household size was 2.56 and the average family size was 3.07.
In the city, the age distribution was 26.9% under 18, 9.5% from 18 to 24, 26.9% from 25 to 44, 22.1% from 45 to 64, and 14.7% who were or older. The median age was 36 years. For every 100 females, there were 77.7 males. For every 100 females 18 and over, there were 78.2 males.
The median income for a household in the city was $27,386 and for a family was $31,250. Males had a median income of $26,136 versus $16,731 for females. The per capita income for the city was $12,825. About 16.6% of families and 17.6% of the population were below the poverty line, including 20.2% of those under 18 and 20.5% of those 65 or over.
The city is served by the Petrolia Independent School District and is home to the Petrolia High School Pirates.