Harrisburg is a city in Linn County, Oregon, United States. The population was 2,795 at the 2000 census. According to the United States Census Bureau, the city has a total area of 1.6 square miles (4.2 km²), of which, 1.6 square miles (4.1 km²) of it is land and 0.04 square miles (0.1 km²) of it (2.44%) is water. As of the census of 2000, there were 2,795 people, 989 households, and 751 families residing in the city. The population density was 1,748.8 people per square mile (674.5/km²). There were 1,038 housing units at an average density of 649.5 per square mile (250.5/km²).