As the name suggests, the Hannibal & St. Joseph Railroad opens to connect the city of Hannibal in the northeastern part of Missouri with St. Joseph in the northwestern part of the state. The two cities are the second and third largest in the state of Missouri, and the east-west route proves to be crucial for economic development, postal communication, troop transport, and supply logistics for the Union Army. The line suffers periodic attacks by pro-Confederate bushwhackers, but it remains active throughout the Civil War and, in 1867 with the construction of the Hannibal Bridge,  turns Kansas City into an important western railroad hub on the cattle trade between Chicago and Texas.