Wylie is a city in Collin, Dallas, and Rockwall Counties in the U.S. state of Texas. As of the 2000 census, the city population was 15,132, but recent rapid growth has 2004 estimates suggesting the population is already 25,850. Once solely located in Collin County, Wylie has extended into neighboring Dallas and Rockwall counties. Both Lake Lavon and Lake Ray Hubbard are within easy reach of the city. Since the 2000 census the population has grown 109.3%, making Wylie number 8 on the list of fastest growing cities in the nation. Current population is now listed at 32,696.