Placer County was created in 1851 from Yuba and Sutter Counties. Placer is probably a contraction of the words plaza de oro (the place of gold) and in Spanish means "a place near a river where gold is found." The county derived its name from the numerous places where the method of extracting gold from the earth, called placer mining, was practiced. Territory that was once in Placer County is now in El Dorado and Sutter Counties.

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