Gil Cisneros defeated Republican Young Kim on Saturday in the last of Orange County’s undecided House races, giving Democrats a clean sweep of the state’s six most fiercely fought congressional contests and marking an epochal shift in a region long synonymous with political conservatism.

With Cisneros’ victory, Democrats will constitute the entirety of Orange County’s seven-member congressional delegation, the first time since the 1930s that the birthplace of Richard Nixon, home of John Wayne and spiritual center of the Republican Party will have no GOP representative in the House.