Route Logic of the Central Pacific Railroad, 1861–1869

The approximate location of the first railroad to reach California from the east had its origins in the congressional debate over slavery prior to the Civil War. The precise location of track took years to define. By comparing two sets of historical maps in the California State Archives, this article examines how the route of the Central Pacific Railroad evolved from a plausible engineering concept to the busy track it is today. This occurred at the hands of Congress, a pharmacist, an engineer, and the engineer’s assistant, in response to national politics, local business concerns, balance sheets, and the limits of railway construction technology in the 1860s.