White settlers were drawn to the area by rumors of gold and by land opened through the
Homestead Act of 1862. The discovery of
rhyolite stone, though, not gold, ultimately led to the settlement of Castle Rock. Castle Rock was founded in 1874 when the eastern Douglas County border was redrawn to its present location. Castle Rock was chosen as the county seat because of its central location. One of the first homesteaders in the area near today's Castle Rock was Jeremiah Gould. He owned about to the south of "the (Castle) Rock". At that time, the settlement consisted of just a few buildings for prospectors, workers, and cowboys. In 1874, Gould donated to the new town, which was also now home to the Douglas County government. Six streets named Elbert, Jerry, Wilcox, Perry, Castle, and Front were laid out to build the actual town of Castle Rock. The courthouse square was defined and about 77 lots, each , were auctioned off for a total profit of
US$3,400. A new train depot brought the
Denver and Rio Grande Railway to the area. During the late 1800s and early 1900s, Castle Rock had a very active rhyolite-quarrying industry. Many immigrants arrived in the area to work in the quarries. In 1936, the town received a donation of land that included its namesake geographical feature. Men employed by the
Works Progress Administration constructed a star atop the butte shortly after Castle Rock received that donation. The star was lit every year from 1936 to 1941. After World War II began, the star was left unlit as a symbol of sacrifice in support of the war effort. On August 14, 1945, shortly after
V-J Day, the star was modified into a V-for-victory symbol. On December 7, 1945, the star was lit for the holiday season. It has been lit every year since around the same time. The town's historic county courthouse, which was built in 1889–1890, burned down on March 11, 1978, the result of arson. Castle Rock's municipal government experienced significant financial difficulties during the early 1980s. In 1984, the town's voters approved a charter amendment that authorized the creation of a
home-rule charter commission. The home-rule charter was finalized in 1987. The original Douglas County courthouse was one of seven buildings in Castle Rock that have been added to the
National Register of Historic Places. The other buildings include
Castle Rock Depot, Castle Rock Elementary School, First National Bank of Douglas County, Samuel Dyer House, Benjamin Hammer House, and Keystone Hotel. A dispute about whether the Castle Rock Police Department was required to enforce a civil restraining order was decided by the
U.S. Supreme Court in 2005. The court held, in
Town of Castle Rock v. Gonzales, that a municipality cannot be held liable under a federal civil-rights statute,
42 U.S.C. § 1983, for failing to enforce civil restraining orders. The case had arisen from a 1999 murder of three young girls by their father outside the Castle Rock Police Department building. The children were killed by their father, in violation of the restraining order that had been obtained by their mother, within several hours of being abducted. The mother had asked the Castle Rock police to enforce the restraining order by finding and apprehending the father after he removed the children from her home and before the murders. Castle Rock police officers declined to do so, refusing even to contact the Denver Police Department after the mother notified them that the father had taken the children to an amusement park in that city. ==Geography==