Del Mar
Though it's San Diego County's smallest city in both size and population, Del Mar is one of its most widely known due to prominence of its Del Mar Race Track & Fairgrounds. The City of Del Mar with about 2 square miles of land for its 5,211 residents, the city gives up almost one quarter to the fairgrounds. But its beaches stretch from Del Mar Shores Beach Park in the north edge of Torrey Pine State Reserve and the La Jolla Underwater Park in the south.