Guatay is an unincorporated community in the Cuyamaca Mountains, in the Mountain Empire area of southeastern San Diego County, California.The town's elevation is 3,999�feet. Although Guatay is unincorporated, it has a post office, with the ZIP code of 91931.It was the location of a 19th-century stagecoach station on the San Antonio-San Diego Mail Line.Nearby Guatay Mountain, a peak of the Cuyamaca Mountains, is home to a grove of the rare endemic Tecate Cypress.