the TriCities, a metropolitan area composed of Richland, Kennewick, Pasco, and smaller communities, and home to nearly 300,000 residents. Hanford is a primary economic base for these cities. In 2000 large portions of the original site were turned over to the Hanford Reach National Monument. The remainder was divided by function into three main areas: the nuclear reactors were located along the river in an area designated as the 100Area; the chemical separations complexes were located inland in the Central Plateau, designated as the 200Area; and support facilities were located in the southeast corner of the site, designated as the 300 Area. Climate Hanford is the site of Washington state's highest recorded temperature of , reached on June 29, 2021. Early history The confluence of the Yakima, Snake, and Columbia rivers has been a meeting place for native peoples for centuries. The archaeological record of Native American habitation of this area stretches back over ten thousand years. Tribes and nations including the Yakama, Nez Perce, and Umatilla used the area for hunting, fishing, and gathering plant foods. Archaeologists have identified numerous Native American sites, including "pit house villages, open campsites, fish farming sites, hunting/kill sites, game drive complexes, quarries, and spirit quest sites", and two archaeological sites were listed on the National Register of Historic Places in 1976. In 1855 Isaac Stevens, the governor of the Territory of Washington, negotiated with the Native American tribes to establish a reservation system. Treaties were signed, but were often ignored, as the reservation system they mandated was not compatible with traditional food-gathering or family groupings. In September 1858 a military expedition under Colonel George Wright defeated the Native American tribes in the Battle of Spokane Plains to force compliance with the reservation system. Nonetheless, Native American use of the area continued into the 20th century. The Wanapum people were never forced onto a reservation, and they lived along the Columbia River in the Priest Rapids Valley until 1943. After gold was discovered in British Columbia, prospectors explored the Columbia River basin in search of gold, but with little success. Walla Walla, which had been established as a military post in 1858, became a center for mining supplies, and a general store was established at White Bluffs. A ranch was established in Yakima Valley by Ben Snipes in 1859, and the Northern Pacific Railroad was extended into the area beginning in 1879. The railroad