Montebello is a city in Los Angeles County, California, United States, located in the southwestern area of the San Gabriel Valley on 8.4sqmi 8mi east of downtown Los Angeles. It is considered part of the Gateway Cities, and is a member of the Gateway Cities Council of Governments. In the early 20th century, Montebello was a well-known source for oil reserves. At the 2010 census, the population was 62,500. The estimated population as of July 1, 2013 was 63,495.