Washington is a city in south central Washington County, Utah, United States and is a part of the St. George Metropolitan Area. The area is also known as Utah's Dixie because the Mormon pioneers that settled the St. George area came to the area to raise cotton, which was milled at the cotton mill in Washington. The population was 8,186 at the 2000 census, and 18,761 as of the 2010 Census. Washington is a suburb of St. George, and is the second largest city in Washington County.The city was named after U.S. President George Washington. The city administration has tried to encourage the use of the name "Washington City" in recent years. The U.S. Post Office lists "Washington, UT 84780.