Douglas County grew 191 percent between 1990 and 2000 making it the fastest growing county in the U.S. in the decade. It grew another 63 percent from 2000 to 2007, ranking 11th nationally. Much of that growth has occurred in the town of Castle Rock. With an expected annual growth rate of about 6 percent per year once the housing downturn eases, it is estimated that the Town population will reach 100,000 in 2060. The Town is basing water plans on that anticipated population figure.According to the Town of Castle Rock, there are approximately just under 50,000 residents living within Town limits. Within a 10-mile radius of that downtown intersection, ESRI asserts that there are about 100,000 people. This distance counts residents of Perry Park (part), Sedalia, Castle Pines, The Pinery, Parker (southern tip) and Franktown.