This Map of the Territory of New Mexico is based on the topographical sketches made by Lieutenant W. G. Peck in 1846-7 under the Order of Brig. General S.W. Kearny and published by the War Department in 1847.

This strategically important map was made in preparation for the annexation of the Spanish-held territories of Texas and New Mexico and, ultimately, the Mexican War. In addition to the established routes to and from the colonial Spanish capitol of Santa Fe, the map provides comprehensive and intricate details of the local topography.

Finally engraved contour lines suggest the steepness of canyon walls surrounding the many rivers and streams. Areas of "High Table Lands — no running water" are indicated along with annotations of ground cover vegetation. Forested zones are shown by tiny, intricately drawn trees of several types.