Los Angeles, Colorado

In 1859, nine years after California joined the Union and a couple years before the Civil War, state Assemblyman Andrés Pico introduced a bill that called for the secession of the five southern counties--Los Angeles, Santa Barbara, San Bernardino, San Diego, and San Luis Obispo. He wanted southern California to re-form as a federal territory named after the Colorado River (Colorado wasn't named until 1861). The legislature passed the bill, the governor signed it, and two-thirds of voters in the affected counties approved it. [KCET]