History
* 1771 – Mission San Gabriel Arcangel founded on present-day San Gabriel.
* 1801 – Pío Pico, last Mexican governor of Alta California, born at Mission San Gabriel Arcangel.
* 1847 – Battle of Rio San Gabriel—in present-day Montebello—of the Mexican-American War; Mexican militia retreats. (Two days later, after several battle losses and defeats, Mexico is forced to cede Alta California to the United States.)
* 1886 – Pasadena is the first independent incorporated city in Los Angeles County.
* 1890 – The first Tournament of Roses Parade is presented in Pasadena.
* 1920 – The California Institute of Technology or Caltech opens in Pasadena. Japanese immigrants arrive in Monterey Park to work as farmhands.
* 1941 – The first freeway in the United States, Arroyo Seco Parkway (now the 110 Pasadena Freeway), opens.
* 1942 – Japanese Americans interned at Santa Anita Park during World War II.
* 1940s-1950s – San Gabriel Valley changes from acres of farmland to suburban bedroom communities.
* 1957 – San Bernardino Freeway (Interstate 10) opens.
* 1970s-1980s – Taiwanese immigrants begin settling in Monterey Park.
* 1980s – Present – Mainland Chinese and Hong Kong (1980-1990) immigrants began to settle to Monterey Park, Alhambra, Rosemead, El Monte and San Gabriel. Taiwanese (in the 1990s) moved to affluent areas such as San Marino, Arcadia, Rowland Heights, Hacienda Heights and Walnut.
