Grants began as a railroad camp in the 1880s, when three Canadian brothers – Angus A. Grant, John R. Grant, and Lewis A. Grant – were awarded a contract to build a section of the new Atlantic and Pacific Railroad through the region. The Grant brothers' camp was first called Grants Camp, then Grants Station, and finally Grants. The new city enveloped the existing colonial New Mexican settlement of Los Alamitos and grew along the tracks of the Atlantic and Pacific Railroad.
The town prospered as a result of railroad logging in the nearby Zuni Mountains, and it served as a section point for the Atlantic and Pacific, which became part of the Atchison, Topeka, and Santa Fe railroad empire. The Zuni Mountain Railroad short line had a roundhouse in town (near present day Exit 81 off Interstate 40) and housed workers in a small community named Breecetown. Timber from the Zuni Mountains was shipped to Albuquerque where a large sawmill converted the timber to wood products that were sold around the west.
After the decline of logging in the 1930s, Grants gained fame as the "carrot capital" of the United States. Agriculture was aided by the creation of Bluewater Reservoir, and the region's volcanic soils provided ideal conditions for farming. Grants also benefited from its location on U.S. Route 66, which brought tourists and travelers and the businesses that catered to them.
Perhaps the most memorable boom in the town's history occurred when Paddy Martinez, a Navajo shepherd, discovered uranium ore near Haystack Mesa, sparking a mining boom that lasted until the 1980s. The collapse of mining pulled the town into a depression, but the town has enjoyed a resurgence based on interest in tourism and the scenic beauty of the region. Recent interest in nuclear power has revived the possibility of more uranium mining in the area, and energy companies still own viable mining properties and claims in the area.