Moraga is a town in Contra Costa County, California, in the San Francisco Bay Area. The town is named in honor of Joaquín Moraga, member of the famed Californio family, son of Gabriel Moraga, and grandson of José Joaquín Moraga, famous 18th century expeditionaries of the Californias. Moraga incorporated in 1974, when the communities of Moraga Town, Rheem, and Rheem Valley, united into one town.