| Official Name: | Petrolia, Pennsylvania |
| Settlement Type: | Borough |
| Pushpin Map: | Pennsylvania |
| Pushpin Label: | Petrolia |
| Pushpin Label Position: | right |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Pennsylvania |
| Subdivision Type2: | County |
| Subdivision Name2: | Butler |
| Government Type: | Borough Council |
| Leader Title: | Mayor |
| Established Title: | Settled |
| Established Date: | 1872 |
| Established Title1: | Incorporated |
| Established Date1: | 1873 |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 1.02 |
| Area Land Km2: | 1.02 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 0.40 |
| Area Land Sq Mi: | 0.40 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Footnotes: | [2] |
| Population Total: | 179 |
| Population Density Km2: | 175.07 |
| Population Density Sq Mi: | 453.16 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Coordinates: | 41.0181°N -79.7183°W |
| Elevation Ft: | 1178 |
| Postal Code Type: | Zip code |
| Postal Code: | 16050 |
| Blank Name: | FIPS code |
| Blank Info: | 42-59672 |
Petrolia is a borough in Butler County, Pennsylvania, United States. The population was 212 at the 2010 census.[3]
Petrolia is located in eastern Butler County at 41.0181°N -79.7183°W (41.017964, −79.718204),[4] in the valley of the South Branch of Bear Creek, a tributary of the Allegheny River.
Pennsylvania Route 268 passes through the borough, leading north 3miles to Bruin and south to Karns City.
According to the United States Census Bureau, Petrolia has a total area of 1km2, all land.[3]
As of the 2000 census, there were 218 people, 89 households, and 64 families residing in the borough. The population density was 543.7sp=usNaNsp=us. There were 99 housing units at an average density of 246.9sp=usNaNsp=us. The racial makeup of the borough was 100.00% White.
There were 89 households, out of which 29.2% had children under the age of 18 living with them, 53.9% were married couples living together, 11.2% had a female householder with no husband present, and 27.0% were non-families. 20.2% of all households were made up of individuals, and 6.7% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 2.80.
In the borough the population was spread out, with 21.1% under the age of 18, 8.3% from 18 to 24, 34.4% from 25 to 44, 23.9% from 45 to 64, and 12.4% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 89.6 males. For every 100 females age 18 and over, there were 93.3 males.
The median income for a household in the borough was $29,821, and the median income for a family was $37,708. Males had a median income of $31,875 versus $23,750 for females. The per capita income for the borough was $17,358. About 8.5% of families and 14.5% of the population were below the poverty line, including 23.1% of those under the age of eighteen and none of those sixty five or over.