Rattlesnake Mountain, Benton County, Washington
The view of Rattlesnake Mountain from the Horn Rapids Golf Course in Richland.
|Elevation||3,527 ft (1,075 m)|
|Location||Benton County, Washington, U.S.|
Rattlesnake Mountain (Native American name Lalíik meaning "land above the water") is a 3,527 ft (1,060 m) windswept treeless sub-alpine ridge overlooking the Hanford nuclear site. Parts of the western slope are privately owned ranchland, while the eastern slope is under the federal protection of the Arid Lands Ecology Reserve, a unit of the Hanford Reach National Monument, managed by the United States Fish and Wildlife Service.
Rattlesnake Mountain is often described as the tallest treeless mountain in the world, but this claim appears to be without foundation. The highest winds recorded on Rattlesnake were around 150 mph (241 kilometers per hour).
The Yakama Nation referred to Rattlesnake Mountain as Lalíik, meaning "land above the water". Some historians speculate that the origin of the name Lalíik refers to the inundation of the Columbia River Plateau during the Missoula Floods, as Rattlesnake would have been one of the few mountains not completely inundated by flood waters reaching depths of 1200 ft (366 m). Geologists have found glacial erratics on Rattlesnake at heights up to this level. However, there is scant evidence placing human settlements in the area at the time of the floods, 12 to 13 thousand years ago. Lalíik is held sacred by native peoples of the Columbia Plateau, including the Nez Perce, Umatilla, Wanapum, Cayuse, Walla Walla, and Yakama, and remains a spiritual epicenter to this day.
In 1943, Rattlesnake Mountain was seized by the United States government under eminent domain and became a buffer zone for the nuclear project at the Hanford site. In 1956, the Army installed a Nike Ajax missile base on the southeastern end of the ridge and maintained it until 1960, when it was closed.
Rattlesnake Mountain Observatory
The Rattlesnake Mountain Observatory was established at the summit in 1966, utilizing some of the former missile base infrastructure. The observatory's main telescope was installed in 1971 and is a 32 inch (0.8-meter) telescope housed inside a 24 foot domed enclosure. This telescope is the largest permanently mounted telescope in Washington State. The telescope was used regularly through the early 1980s, but soon fell into disuse. Due to its location, renovations and upgrades were done to allow for remote control. Observatory operations are directed by a local nonprofit group founded by scientists and engineers from the Pacific Northwest National Laboratory at Hanford.
It was announced 14 March 2008 that the Department of Energy is not renewing the permit, license or easements for the observatory or any of the other entities that maintain communication equipment on the mountain. DOE instead intends to return the area to its natural conditions citing the cultural sensitivity to the area. The removal of the observatory from Rattlesnake Mountain began in the latter part of May, 2009. Most of the work, including the removal of the telescope itself, was completed in June of the same year. In late 2012, the telescope moved into its new home in the hills near Wallula, WA 
The Rattlesnake Mountain Public Access Act (H.R. 1157) is a bill that has been introduced into the United States House of Representatives during the 113th United States Congress. The bill would require the United States Secretary of the Interior to provide public access to the summit of Rattlesnake Mountain in the Hanford Reach National Monument in the state of Washington. The bill is supposed to help with tourism and scientific undertakings. It passed the House on June 11, 2013 and was sent to the Senate.
- The Alliance for the Advancement of Science Through Astronomy: Rattlesnake Mountain Observatory
- Department of Energy Hanford Site Virtual Tours: Rattlesnake Mountain
- "Rattlesnake Mountain". Geographic Names Information System, U.S. Geological Survey. Retrieved 2013-01-25.
- Davis, Jean Carol; Vickie Sillman Bergum. Benton County Place Names. East Benton County Historical Society. ISBN [[Special:BookSources/33629001556692|33629001556692 [[Category:Articles with invalid ISBNs]]]] Check
- "Hanford Site Virtual Tours". Department of Energy. Archived from the original on 2007-07-07. Retrieved 2007-10-13.
- Bjornstad, Bruce; Karl Fecht (2002-10-19). "Ice-Age Floods Features in the Vicinity of the Pasco Basin and the Hanford Reach National Monument" (.pdf). Retrieved 2007-11-07.
- "Automation of Rattlesnake Mountain Observatory--Science Education and Opportunity for the 21st Century". Retrieved 2007-10-12.
- Cary, Annette (2008-03-22). "DOE to evict Rattlesnake Mountain tenants". Tri-City Herald.
- "Rattlesnake Mountain telescope gets new home". Retrieved 2013-01-06.
- "CBO - H.R. 1157". Congressional Budget Office. Retrieved 12 June 2013.
- Kasperowicz, Pete (11 June 2013). "To the top of Rattlesnake Mountain". The Hill. Retrieved 13 June 2013.