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.
Geography
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.<br>2020 Census
| align-fn = center
As of the 2020 census, Petrolia had a population of 514.
Racial and ethnic composition
{| class="wikitable"
|+ Racial composition as of the 2020 census
! Race !! Number !! Percent
|-
| White || 432 || 84.0%
|-
| Black or African American || 3 || 0.6%
|-
| American Indian and Alaska Native || 2 || 0.4%
|-
| Asian || 1 || 0.2%
|-
| Native Hawaiian and Other Pacific Islander || 0 || 0.0%
|-
| Some other race || 13 || 2.5%
|-
| Two or more races || 63 || 12.3%
|-
| Hispanic or Latino (of any race) || 39 || 7.6%
|}
2020 census
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.
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.