The P Ranch is a historic ranch in Harney County in southeastern Oregon, United States. The remaining ranch structures are located on the west bank of the Donner und Blitzen River in the Malheur National Wildlife Refuge. The ranch was built by Peter French, a well known 19th-century cattle baron. The P Ranch became headquarters for the French-Glenn Livestock Company, which eventually covered over 140,000 acres (570 km2). After French was murdered in 1897, the French-Glenn Livestock Company slowly sold off the P Ranch property. In 1935, the United States Government purchased the remaining P Ranch property to add to an adjacent wildlife refuge. The Civilian Conservation Corps demolished most of the original ranch buildings in the 1930s, and a fire destroyed the main ranch house in 1947. The few remaining P Ranch structures are now listed on the National Register of Historic Places.

The Donner und Blitzen River is a river on the eastern Oregon high desert that drains a relatively arid basin, the southern portion of Harney Basin, from roughly 20 to 80 miles south-southeast of Burns including Malheur National Wildlife Refuge. Though much of its course is marsh, it offers scenic glaciated canyons, unique ecosystems, and exceptional wild trout fisheries. Named by soldiers of German origin, the Donner und Blitzen River translates as "thunder and lightning". The name usually brings to mind two of Santa Claus's reindeer, but the river is named for a thunderstorm the soldiers experienced as they crossed the river; dry lightning is an almost daily occurrence in the region during certain times of the year.