<P> During the late 1800s and early 1900s, Castle Rock had a very active Rhyolite quarrying industry . Many Swedish immigrants arrived in the area to work in the quarries . </P> <P> Castle Rock currently encompasses about 35 square miles (91 km), with a population of more than 42,000 in town and 70,000 in the surrounding area . </P> <P> Castle Rock is located at 39 ° 22 ′ 20" N 104 ° 51 ′ 22" W ﻿ / ﻿ 39.37222 ° N 104.85611 ° W ﻿ / 39.37222; - 104.85611 (39.372212, - 104.856090) at an elevation of 6,224 feet (1,897 m). Located in central Colorado at the junction of Interstate 25 and State Highway 86, Castle Rock is 28 mi (45 km) south of downtown Denver and 37 mi (60 km) north of Colorado Springs . </P> <P> The town lies a few miles east of the Rampart Range of the Rocky Mountains on the western edge of the Great Plains . Castle Rock, the butte that is the town's namesake, sits just north of the town center . Other prominent landforms visible from Castle Rock include Dawson Butte, Devils Head, Mount Evans and Pikes Peak . </P>

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