Denver is a borough in Lancaster County, Pennsylvania, United States. The population was 3,332 at the 2000 census. Founded by Hans Bucher, a Swiss immigrant, in 1735. Soon after it was called Bucher's Thal. In the 1800s a train station was built and the town was renamed Union Station. Residents were growing weary of being referred to as a train station so in 1881, after researching post offices in the country, Adam Brubaker found only one named Denver. On November 1, 1881 the town was officially renamed Denver.