Placentia (/pləˈsɛnʃə/) is a city in northern Orange County, California. The population was 51,233 during the 2020 census, up from 46,488 in the 2000 census. This includes the community of Atwood, which is included in the city of Placentia, and is located in its southeastern quadrant. Primarily referred to as a bedroom community, Placentia is known for its quiet neighborhoods. In 1971, Placentia was honored with the prestigious "All America City" Award, given out annually by the National Civic League to ten cities in the United States.