thumb|Benton County, Washington

Benton County is a county in the south-central portion of the U.S. state of Washington. As of the 2020 census, its population was 206,873. The county seat is Prosser, and its most populous city is Kennewick. The Columbia River demarcates the county's north, south, and east boundaries.

Benton County was created from what were then larger versions of Klickitat County and Yakima County on March 8, 1905, and was named after Missouri statesman Thomas Hart Benton.

Geography

According to the United States Census Bureau, the county has a total area of , of which is land and (3.4%) is water. The highest point of land elevation within the county is the summit of Rattlesnake Mountain at 3,527 feet; and the lowest point of land elevation is along the southwestern shore of Crow Butte at 265 feet (fluctuates due to level of Columbia River).

Waterways

  • Columbia River - Surrounds and forms the county's boundary on three sides. Barge trafficking is possible upriver to anchorage sites in northern Richland, the upstream extent of Lake Wallula which forms behind McNary Dam.
  • Yakima River - Bisects the county from west to east, emptying into the Columbia River at Richland. As a water source, the Yakima is the lifesource for agriculture in the Yakima Valley. A shallow river, the Yakima is suitably navigable only for small, personal watercraft. Historically, the Yakima River supported some of the most bountiful migratory fish populations in the entire Columbia Basin, and many of those legendary salmon runs are now rebounding after decades of demise. Amon Creek is the most notable tributary of the Yakima River in Benton County, emptying into the mainstem river near the Yakima River Delta in Richland.

Mountains and ridges

  • Horse Heaven Hills
  • Rattlesnake Hills
  • Lookout Summit
  • Rattlesnake Mountain
  • Jump Off Joe
  • Badger Mountain
  • Candy Mountain
  • Red Mountain

Adjacent counties

  • Grant County - north
  • Franklin County - northeast
  • Walla Walla County - east
  • Umatilla County, Oregon - southeast
  • Morrow County, Oregon - southwest
  • Klickitat County - southwest
  • Yakima County - west

National Protected Areas

  • Hanford Reach National Monument (part)
  • Manhattan Project National Historical Park (part)
  • Saddle Mountain National Wildlife Refuge (part)
  • Umatilla National Wildlife Refuge (part)

Major highways

  • 20px Interstate 82
  • 23px Interstate 182
  • 20px U.S. Route 12
  • 23px U.S. Route 395
  • 20px Washington State Route 14
  • 20px Washington State Route 240
  • 20px Washington State Route 397

Demographics