Between the 1860s and the early 1900s, the western United States underwent one of the most dramatic reorganizations of people, land, capital, and resources in American history. Paper Trails tells a new history of the nation's western expansion by shining a light on the era's largest government institution: the US Post.

The Congressional Record is the official record of the proceedings and debates of the United States Congress. It is published daily when Congress is in session. The Congressional Record began publication in 1873. Debates for sessions prior to 1873 are recorded in The Debates and Proceedings in the Congress of the United States (1789-1824), the Register of Debates in Congress (1824-1837), and the Congressional Globe (1833-1873)