~ John Day Dam ~ Washington Dam 
~ 109 miles from PDX.
John Day Dam is located at the head of Lake Celilo, 216 miles upstream from the mouth of the Columbia River and creates Lake Umatilla. The dam crosses the Columbia River near Rufus, Oregon, about 25 miles upstream from The Dalles, just below the mouth of the John Day River. The closest town on the Washington side is Goldendale, 20 miles (32 km) north.
The John Day Dam is 219 ft (67 m) high and 5,640 ft (1,719 m) long, on the Columbia River between Oregon and Wash.; built between 1959 and 1968 by the U.S. Army Corps of Engineers. It is an extremely large generator of hydroelectric power. The dam's reservoir regulates navigation upstream; locks provide ship passage from The Dalles Dam reservoir to Mc Nary Dam.
A note on roads: if you are so inclined to get Horn Rapids from here, take a great motorcycle trip out of Goldendale, through Bickleton, Mabton and up. :-)
GPS: 45.71806 ° N - 120.69278° W or 45° 43’ 05.02" N - 120° 41’ 34.01"W
(Click or drag Map for interactive view.)
