The Territory of New Mexico was an organized incorporated territory of the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 that existed from September 9, 1850, until January 6, 1912, when the final extent of the territory was admitted to the Union as the State of New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

.
The Congressional Compromise of 1850

Compromise of 1850

The Compromise of 1850 was a package of five bills, passed in September 1850, which defused a four-year confrontation between the slave states of the South and the free states of the North regarding the status of territories acquired during the Mexican-American War...

 halted a bid for statehood under a proposed antislavery constitution, and bounded by the Arkansas River

Arkansas River

The Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...

 (the former US-Mexico border) from its source to the 100th meridian west

100th meridian west

The meridian 100° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole....

, south to just south of the 32nd parallel north

32nd parallel north

The 32nd parallel north is a circle of latitude that is 32 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Pacific Ocean, North America and the Atlantic Ocean....

, west passing north of El Paso

El Paso

El Paso, a city in the U.S. state of Texas, on the border with Mexico.El Paso may also refer to:-Geography:Colombia:* El Paso, CesarSpain:*El Paso, Santa Cruz de TenerifeUnited States:...

, then along the new US-Mexico border set by the Treaty of Guadalupe Hidalgo

Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo is the peace treaty, largely dictated by the United States to the interim government of a militarily occupied Mexico City, that ended the Mexican-American War on February 2, 1848...

 until the 111th meridian west

111th meridian west

The meridian 111° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole....

, north to the Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

, then a diagonal straight line back to the source of the Arkansas River.