Grande Ronde Valley

Grande Ronde Valley
Elevation map of Union County, with the Grande Ronde Valley featured in the center.
Floor elevation820 m (2,690 ft)
Length35 miles North to South
Width15 miles
Geology
TypeFlood basalt
Geography
LocationUnion County, Oregon, United States
Borders onBlue Mountains
RiversGrand Ronde River

The Grande Ronde Valley is a valley in Union County in northeastern Oregon, United States. It is surrounded by the Blue Mountains and Wallowa Mountains, and is drained by the Grande Ronde River. La Grande is its largest community. The valley is 35 miles (56 km) long, north to south, from Pumpkin Ridge to Pyles Canyon, and 15 miles (24 km) wide, east to west, from Cove to the Grande Ronde River's canyon. Its name, fittingly, means, "great circle."