Denver is a borough in Lancaster County, Pennsylvania, United States. The population was 3,332 at the 2000 census. According to the United States Census Bureau, the borough has a total area of 1.3square miles (3.4Square kilometers), all of it land. As of the census of 2000, there were 3,332people, 1,266households, and 944families residing in the borough. The population density was 2,550.8people per square mile (982.1Square kilometers). There were 1,298housing units at an average density of 993.7per square mile (382.6Square kilometers).