The cities are located at the confluence of the Yakima, Snake, and Columbia rivers in the semi-arid region of Southeastern Washington.A fourth neighboring city, West Richland, is generally included as part of the Tri-City area and region.It also had the most land for easy irrigation and farming and was still the largest up until the founding of Hanford near Richland.
Kennewick was incorporated in 1904, and Richland followed in 1910.
West Richland was founded by dissatisfied residents of Richland, who wished to be home owners rather than renters of government-owned houses, after the arrival of Hanford.
(The Richland High School student newspaper is called the ) Thanks to the aforementioned rivers, a large amount of cheap irrigation is available.
Washington is the most northwest of the lower 48 states—consequently, the area is in the Pacific Standard Time Zone.
The Columbia Center Mall was built on land newly incorporated into Kennewick, drawing growth to western Kennewick and south Richland.
With the end of the Cold War, many in the area feared a shutdown of Hanford, followed by the Tri-Cities quickly becoming a ghost town.
Despite attempts by Richland to annex the community, they remained separate and eventually became incorporated in 1955.
Pasco was the largest city in the Tri-Cities, mostly due to its railroad station.
Richland's Columbia High School adopted "Bombers" as its mascot (complete with mushroom cloud logo).
In 1970, Kamiakin High School (in the neighboring city of Kennewick) was founded in response to the continued influx of people.
In 1995, a sixth public high school, Southridge High, was founded in south Kennewick.