Many layers of rock and sedimentary material containing fossils can be seen on the bluffs in and around Oil City. Oil City is framed by the surrounding foothills with the Allegheny River winding through downtown.
The Allegheny River at Oil City freezes occasionally during the winter which may sometimes result in ice jams. Flooding of the River Flats is a possibility throughout the year due to ice jams, excessive snow melt, large volume storms and hurricane & tropical storm remnants.
Barges were used to transport the oil down Oil Creek and into Oil City, where it was transported to steamboats or bulk barges to continue on to Pittsburgh and other locations. Oil City was founded in 1860, incorporated as a borough in 1863, and chartered as a city in 1874. The Borough of Oil City was incorporated as a city in 1871. The city was partially destroyed by flood in 1865 and by both flood and fire in 1866 and again in 1882; on this last occasion, several oil tanks that were struck by lightning gave way, and Oil Creek carried a mass of burning oil into the city, where some 60 lives were lost and property valued at more than $1 million was destroyed. Oil City grew into a thriving community through the later half of the 19th century and into the 20th Century. By the 1990s, Pennzoil, Quaker State and Wolf's Head had all relocated headquarters elsewhere. However, some oil wells continue to produce a steady supply of quality petroleum.
The region promotes tourism by thoroughly educating the public about oil history. Oil City's location along the Allegheny River in the foothills of the Appalachian Mountains provides excellent opportunities for exploring Northwestern Pennsylvania.
There were 4,762 households out of which 30.2% had children under the age of 18 living with them, 44.8% were married couples living together, 12.7% had a female householder with no husband present, and 37.4% were non-families. 32.7% of all households were made up of individuals and 16.0% had someone living alone who was 65 years of age or older. The average household size was 2.37 and the average family size was 2.99.
In the city the population was spread out with 25.8% under the age of 18, 7.9% from 18 to 24, 27.2% from 25 to 44, 21.6% from 45 to 64, and 17.5% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 90.6 males. For every 100 females age 18 and over, there were 84.8 males.
The median income for a household in the city was $29,060, and the median income for a family was $36,149. Males had a median income of $30,072 versus $19,697 for females. The per capita income for the city was $14,696. About 16.2% of families and 19.0% of the population were below the poverty line, including 28.3% of those under age 18 and 12.4% of those age 65 or over.