|Area||2.2 sq mi (6 km2)|
|Density||1,324.1 / sq mi (511 / km2)|
|- summer (DST)||EDT (UTC-5)|
Oliver is located at (39.914359, -79.717139).
According to the United States Census Bureau, the CDP has a total area of 2.2 square miles (5.7 km2), all of it land.
The climate in this area has mild differences between highs and lows, and there is adequate rainfall year round. According to the Köppen Climate Classification system, Oliver has a marine west coast climate, abbreviated "Cfb" on climate maps.
As of the census of 2000, there were 2,925 people, 1,267 households, and 819 families residing in the CDP. The population density was 1,324.1 people per square mile (511.0/km²). There were 1,375 housing units at an average density of 622.4/sq mi (240.2/km²). The racial makeup of the CDP was 91.45% White, 6.91% African American, 0.24% Native American, 0.48% Asian, 0.03% Pacific Islander, 0.10% from other races, and 0.79% from two or more races. Hispanic or Latino of any race were 0.51% of the population.
There were 1,267 households out of which 26.0% had children under the age of 18 living with them, 41.0% were married couples living together, 18.5% had a female householder with no husband present, and 35.3% were non-families. 32.2% of all households were made up of individuals and 17.4% had someone living alone who was 65 years of age or older. The average household size was 2.25 and the average family size was 2.82.
In the CDP the population was spread out with 21.2% under the age of 18, 8.3% from 18 to 24, 24.7% from 25 to 44, 24.5% from 45 to 64, and 21.3% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 82.0 males. For every 100 females age 18 and over, there were 75.4 males.
The median income for a household in the CDP was $23,333, and the median income for a family was $34,402. Males had a median income of $25,531 versus $20,669 for females. The per capita income for the CDP was $13,509. About 13.6% of families and 18.5% of the population were below the poverty line, including 31.3% of those under age 18 and 15.2% of those age 65 or over.