Notes made by land surveyors in 1858 were utilized to estimate cover of grasses and shrubs on the Jornada Experimental Range (JER) and the Chihuahuan Desert Range Research Center (CDRRC) in the northern Chihuahuan Desert, southern New Mexico, USA. Portions of these areas have previously been assessed for historical vegetation dynamics, but the entire 84,271 ha assessed in the 19th century has not been examined in total. In 1858, fair to very good grass cover occurred on 98 and 67 percent of the JER and CDRRC, respectively. Shrubs were present throughout both properties, but 45 percent of the JER and 18 percent of the CDRRC were shrub free. Reconnaissance surveys to determine carrying capacity for livestock, made in 1915-16 and 1928-29 on the JER and in 1938 on the CDRRC, show that shrubs had made large increases in area occupied at the time of the surveys. Vegetation-type maps were made of both properties in 1998. Mesquite (Prosopis glandulosa Torrey) was the primary dominant on 59 percent of the JER in 1998, and creosotebush [Larrea tridentate (Sess. & Moc. Ex DC.) Cov.] was the primary dominant on 27 percent of the area. On the CDRRC, mesquite and creosotebush were primary dominants on 37 and 46 percent of the area, respectively. Grass cover has decreased greatly with the increase in shrubs, and only shrub control efforts have maintained the once abundant black grama [Bouteloua eriopoda (Torrey) Torrey] as a primary dominant on 1 percent or less of the area on both properties. Sustainable use as grazing land will require low levels of use because grasses cannot increase unless shrubs are eradicated and shrub control is likely to remain economically unfeasible for the foreseeable future. http://www.sciencedirect.com/science/article/pii/S0140196304002150