Colorado Territory was created in 1861 for its gold, silver and other mineral resources. Its western boundary was designated as 32 degrees of longitude west of the Washington Meridian. Colorado became a state in 1876. In 1878, U.S. Surveyor Rollin J. Reeves started from the Four Corners Monument and marked a line going north along the boundary of the State of Colorado and the Utah Territory, with a team of surveyors using a 66-foot-long chain and a transit/compass made of wood, glass and brass. The original marked line has been upheld in legal challenges over a more technically precise location. The Four Corners Monument, first set by Chandler Robbins in 1875, has been replaced and upgraded in 1899, 1931, 1962, 1992 and 2010.