The population of Richland City was 67,830 at the 2000 census. During the 1930s, the town had a brief gas boom, when deposits of natural gas were discovered in the Rattlesnake Hills to the northwest of the city. However, the wells were eventually depleted, and the town's population plummeted. With the Great Depression and the subsequent decline in farm prices, Richland City became a sleepy farming town by the end of the century. When World War II began, the city was an unorganized sleepy little town surrounded by Pasco and Kennewick.
The town's history dates back to the early 1900s, when W.R. Amon purchased a farm in the area. He and his son Howard proposed a town site on the north bank of the Yakima River. The townsite was named after Nelson Rich, a state legislator and land developer. In 1906, the city was incorporated as a fourth-class city by the U.S. Post Office.
Located adjacent to Howard Amon Park, the city's community center was designed by ARC Architects of Seattle. It features a scenic riverside view and many rooms for general education and personal enrichment classes. The community center also serves as a community gathering place, hosting many social events and activities. In addition to the rich school district, the city has City Utilities that serve the city's businesses and residents.