Rattlesnake Mountain, Mountain summit in Benton County, Washington, US

Rattlesnake Mountain is a bare ridge in Benton County that rises to approximately 3,531 feet above sea level and stretches across the landscape. The slopes are steep and treeless, creating open terrain that stands out from the surrounding area.

The mountain stood partially above water during the ancient Missoula Floods, which submerged much of the Columbia River Plateau thousands of years ago. These geological events shaped the landscape that surrounds the peak today.

Local tribes including the Yakama Nation call this peak Lalíik, meaning 'land above the water' in their language. The name reflects how the tribes understood this landmark in relation to the water systems around it.

The summit lies within the Hanford Reach National Monument, and the eastern slope is part of the Arid Lands Ecology Reserve managed by the US Fish and Wildlife Service. Section 3081 of the 2015 National Defense Authorization Act directs the Secretary of the Interior to open the summit, including motorized access, but the Yakama Nation objected to motorized access to its sacred site. Access was expected in fall 2019 yet remained closed in October 2020 while a final environmental study was pending.

Wind speeds at this peak reach extreme levels, with recorded gusts exceeding 150 miles per hour (240 kilometers per hour) at the exposed summit. These powerful winds make the ridge one of the windiest locations in the region.