Democrat Gil Cisneros captured a Republican-held U.S. House seat in Southern California, capping a Democratic rout in which the party picked up six congressional seats in the state.
In what had been the last undecided House contest in California, Cisneros beat Republican Young Kim for the state’s 39th District seat.

The Cisneros victory Saturday cements a stunning political realignment that will leave a vast stretch of the Los Angeles metropolitan area under Democratic control in the House.

With Kim’s defeat, four Republican-held House districts all or partly in Orange County, once a nationally known GOP stronghold, will have shifted in one election to the Democratic column. The change means that the county — Richard Nixon’s birthplace and site of his presidential library — will only have Democrats representing its residents in Washington next year.

The Orange County Democratic Party said it’s the first time since 1940 that all seven House seats in the county, home to 3.2 million people, are in Democratic control. Three seats all or partly in the northwestern end of the county are held by Democrats who were easily re-elected.