New Mexico, a territory in the SW. of the United States, is bounded by Colorado, Oklahoma, Texas, Mexico, and Arizona. The area is 122,580 sq. m. - larger than that of Great Britain and Ireland - and the pop. (1880) 119,565; (1900) 195,310. The surface of New Mexico belongs to the great plateau upon which rests the Rocky Mountain system. From an altitude of 6000 to 6500 feet in the north it descends gradually to about 4000 feet along the Mexican border, and sinks to 3000 or 3500 in the Llano Estacado of the south-east. Except in the east the whole region is traversed by broken ranges of mountains having in general a north and south trend. In the northern central part the Santa Fe, Las Vegas, and Taos ranges form part of the main axis of the Rocky Mountains, with peaks over 12,000 feet high. Farther south, and east of the Rio Grande, are numerous broken ranges; and west of the Rio Grande the Sierra Madre rises above the level of the mesa (plateau). These mountains and the intervening mesas are cut by deep canons. Among the mountains, especially in the north-east, are many ' parks' noted for their beauty and fertile soils. The precious metals are found in almost all parts of the territory. Some of the mines were rudely worked by the early Spaniards, who compelled the Pueblos to labour like slaves. Copper and iron occur in valuable deposits, and near Santa Fe are the famous turquoise mines. There are also fields of both bituminous and anthracite coal. Mineral and hot springs are numerous. The great mountain-divide causes the drainage of New Mexico to flow south to the Gulf of Mexico, and west to the Pacific Ocean. The Rio Grande traverses the central part of the territory and receives many tributaries. The Rio Pecos which joins it in Texas drains the south-eastern part. In the north-east are streams which unite to form the Canadian River, and in the west are the headwaters of the San Juan, Little Colorado, and Gila, all affluents of the Colorado. In the river-valleys the soil is fertile and produces excellent crops; and many acres in other sections may be successfully cultivated by irrigation. The climate is healthful, and on the whole remarkably uniform, and the atmosphere is very pure and dry. There are extensive forests on the mountains, and in the hilly regions of the western part of the territory, and on the pastoral plains nutritious grasses which support great numbers of cattle and sheep. Stock-raising is a leading industry; the herds need no housing in the winter.

After the Mexican war, part of the territory was acquired by the United States in 1848 ; additions were made by a later purchase from Mexico, and by a cession from Texas. The bulk of the pop., some 190,000, are Mexicans, or of Mexican descent, and there are 13,150 Indians. The territory when originally organised in 1850 included Arizona and parts of Colorado and California. The scheme for its incorporation in 1906 with Arizona (then to become a state of the Union) was successfully opposed both in and out of the Senate. The principal cities and towns are Santa Fe (the capital), Albuquerque, Las Vegas, Fernandez de Taos, and Socorro.