Robert Millikin, born in Waynesboro, Pennsylvania, apprenticed as a carpenter at the age of seventeen and then worked as a contractor and builder. He moved to Nebraska in 1857 and came to Colorado in 1860 where he engaged in mining at Leavenworth Gulch in Gilpin County. Millikin moved to Golden in 1867 and resumed business as a contractor and builder. Among the structures he built was the County's first courthouse, completed in 1878. Millikin served as Mayor of Golden in 1879.