The Civil War impacted Pacific Northwest development in many ways. As regular military troops left for the War Between the States, those that remained guarded Oregon Trail settlers, developed a transportation infrastructure, and cleared the way for settlement through negotiation, conflict, and displacement of Native people to reservations.

Meanwhile, the slavery debate shaped the racial composition of Oregon and Washington and informed the path to statehood. To learn more about how national events connect to the Pacific Northwest, see this Pacific Northwest Civil War Timeline PDF.