Newcomb is a census-designated place (CDP) in San Juan County, New Mexico, United States. The population was 387 at the 2000 census. It is part of the Farmington Metropolitan Statistical Area. According to the United States Census Bureau, the CDP has a total area of 5.9 square miles (15 km2), all land.
As of the census of 2000, there were 387 people, 123 households, and 84 families residing in the CDP. The population density was 65.1 people per square mile (25.2/km²). There were 138 housing units at an average density of 23.2 per square mile (9.0/km²). The racial makeup of the CDP was 13.70% White, 0.26% African American, 83.20% Native American, 0.52% from other races, and 2.33% from two or more races. Hispanic or Latino of any race were 1.81% of the population.