The land area of Colorado has roots in the Louisiana Purchase (1803), a Spanish land cession pursuant to the Adams-Onis Treaty (1819) the Annexation of Texas (1845) and a Mexican land cession pursuant to the Treaty of Guadalupe Hidalgo (1848). The present-day boundaries, in turn, are the result of a series of mid-nineteenth century legislative initiatives by the federal government.
As part of the Compromise of 1850, Texas, which entered the Union in 1845, traded land to the federal government in exchange for debt relief. Some of that land, along with other federal government holdings (from the 1848 Mexican cession) was organized into the New Mexico and Utah territories – their formation was also a part of the Compromise.
A few years hence, the Kansas-Nebraska Act of 1854 created the territories of Kansas and Nebraska. The Colorado territory was born in 1861 and included portions of the Kansas, Nebraska, New Mexico and Utah territories.The entire Colorado territory would become the State of Colorado 15 years later.
Three meridians (north-south lines) serve as the principal lines of reference for dividing the state into 6 mile square townships.1 The 6th Principal Meridian (longitude 97° 22′ 08″ West) resulted from survey work begun in 1855 and is the reference line for most of Colorado. The corresponding baseline (east-west lines) for the 6th P.M begins at the Missouri River and is marked by a monument on the west side on a bluff overlooking the river at 40° North latitude. The baseline extends west across Colorado. Baseline Road in Boulder follows the baseline.
The New Mexico Principal Meridian (longitude 106° 53′ 12″ West) is the reference line for the San Luis Valley. The corresponding baseline for the New Mexico Principal Meridian runs across New Mexico at 34° 15′ 35″ North latitude. The Ute Principal Meridian (longitude 108° 31′ 59″ West) is the reference line for portions of Mesa and Delta counties on the Western Slope.
A legal description of property locates its township(s) relative to the appropriate baseline (north or south) and meridian (east or west). Property within a township is further defined by section – sections being 1 square mile divisions of a township.
So, for example, the downtown Colorado Springs office for Unified Title Company is located in section 18 of a township that is the 66th west of the 6th P.M. and the 14th south of the baseline.
1. In Colorado, counties are a basic unit of government, but land is divided into survey townships pursuant to centuries old federal legislation – the Land Ordinance of 1785.