Emsworth is a borough in Allegheny County, Pennsylvania, along the Ohio River. The population was 2,449 at the 2010 census.
Emsworth is located at 40°30′44″N 80°5′44″W (40.512318, -80.095577).
According to the United States Census Bureau, the borough has a total area of 0.7 square miles (1.8 km2), of which 0.6 square miles (1.6 km2) is land and 0.1 square miles (0.26 km2), or 16.18%, is water.
Emsworth has two land borders with Kilbuck Township from the west to the east and Ben Avon to the southeast. Across the Ohio River's main channel, Emsworth runs adjacent with Neville Township.
At the 2000 census there were 2,598 people in 1,153 households, including 642 families, in the borough. The population density was 4,519.1 people per square mile (1,759.8/km2). There were 1,228 housing units at an average density of 2,136.0 per square mile (831.8/km2). The racial makeup of the borough was 94.42% White, 3.58% African American, 0.04% Native American, 1.15% Asian, 0.04% from other races, and 0.77% from two or more races. Hispanic or Latino of any race were 0.42%.
There were 1,153 households, 24.3% had children under the age of 18 living with them, 42.5% were married couples living together, 10.0% had a female householder with no husband present, and 44.3% were non-families. 38.7% of households were made up of individuals, and 10.9% were one person aged 65 or older.