The Civil War in Oregon mostly involved guarding reservations or pursuing Indians who were masters of escape in their own homelands. When war came to the east, the U.S. Government decided to pull their troops from the Oregon forts, leaving the citizens without military protection. In central and eastern Oregon where gold discoveries generated a rapid influx of miners and settlers, federal and state officials scrambled to find replacement troops. The Department of the Pacific raised recruits and dispatched companies of California Volunteers to Fort Yamhill, Fort Hoskins, and Siletz Blockhouse. The Army abandoned Fort Umpqua in 1862.
East of the Cascades the troops had active engagement.