Emlenton is a borough located mostly in Venango County, in the southeastern corner of the county, with a small portion located in Clarion County in Pennsylvania. The population was 784 at the 2000 census. The borough is also home to the I-80 Emlenton Bridge, which spans the Allegheny River.
According to the United States Census Bureau, the borough has a total area of 0.9 square miles (2.3 km2), of which, 0.8 square miles (2.1 km2) of it is land and 0.1 square miles (0.26 km2) of it (7.87%) is water.
As of the census of 2000, there were 784 people, 322 households, and 200 families residing in the borough. The population density was 947.1 people per square mile (364.7/km²). There were 360 housing units at an average density of 434.9 per square mile (167.5/km²). The racial makeup of the borough was 98.85% White, 0.26% Native American, 0.38% Asian, and 0.51% from two or more races.