The 28th Congressional District includes the cities and unincorporated areas of Arcadia, Alhambra, Altadena, Claremont, Glendora, La Cañada Flintridge, La Crescenta/Montrose, Los Angeles, Lytle Creek, Monrovia, Monterey Park, Pasadena, Rancho Cucamonga, Rosemead, San Gabriel, San Marino, Sierra Madre, South Pasadena, Temple City, Upland, and Wrightwood.