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Orange County is a county in the U.S. state of California.As of the 2010 census, the population was 3,010,232 making it the third-most populous county in California, the sixth-most populous in the United States, and more populous than twenty-one U.S. states.


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This is a list of the National Register of Historic Places listings in Orange County, California.. This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Orange County, California, United States.