Pasco is a city in and the county seat of Franklin County, Washington, United States. Pasco is one of three cities that make up the Tri-Cities region of the state of Washington. The Tri-Cities is a mid-sized metropolitan area of approximately 271,124 people that also includes the cities of Kennewick and Richland in 2013 estimate. The population was 59,781 at the 2010 census and 77,700 at the April 1, 2014 Washington State Population estimate.

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