Montclair is a city in San Bernardino County, California, United States. The population was 36,664 at the 2010 United States Census.
The current mayor is Paul M. Eaton.
Montclair is bordered by Pomona to the West, Claremont and Upland to the North, Ontario to the East and Chino to the South and is in San Bernardino County. Montclair is in the Pomona Valley and part of the Inland Empire. The San Bernardino Freeway (10 Fwy.) runs through the northern part of the city.