Camp Abbot Historical Site, Sunriver

Sixteen months. That's all Camp Abbot lasted — a 5,500-acre combat engineer training center carved out of central Oregon along the Deschutes River south of Bend, active from late 1942 until June 1944. In that window, over 90,000 soldiers cycled through 17-week courses in rifle marksmanship, demolition, and bridge construction under simulated combat conditions. Almost nothing survives. The officers' mess hall — now Sunriver Resort's Great Hall, still used for events — is the only original structure standing.