Bel Air is a residential neighborhood on the Los Angeles Westside, in the foothills of the Santa Monica Mountains in the U.S. state of California. Together with Beverly Hills and Holmby Hills, Bel Air forms the Platinum Triangle of Los Angeles neighborhoods. Along with Beverly Hills and the Los Angeles community of Brentwood, Bel Air is also part of a high-p…Bel Air is a residential neighborhood on the Los Angeles Westside, in the foothills of the Santa Monica Mountains in the U.S. state of California. Together with Beverly Hills and Holmby Hills, Bel Air forms the Platinum Triangle of Los Angeles neighborhoods. Along with Beverly Hills and the Los Angeles community of Brentwood, Bel Air is also part of a high-priced area on the Westside known as the "three Bs."