Walnut is a neighborhood in Irvine, California with a population of 7,616. Walnut is in Orange County and is one of the best places to live in California. Living in Walnut offers residents a dense suburban feel and most residents own their homes. In Walnut there are a lot of restaurants, coffee shops, and parks. Many families and young professionals live in Walnut and residents tend to be liberal. The public schools in Walnut are highly rated.