Muscoy is a census-designated place in San Bernardino County, California, United States. The population was 10,644 at the 2010 census, up from 8,919 at the 2000 census. Muscoy shares ZIP code 92407 with the communities of Verdemont, Devore Heights, Rosena Ranch and Arrowhead Farms in northwestern San Bernardino. Residents enjoy a semi-rural setting with large lots where they can raise horses and other livestock, nursery plants, and fruit trees.