Dillon Beach is a census-designated place (CDP) in Marin County, California, United States. Dillon Beach is located 3.25 miles (5.2 km) west of Tomales, at an elevation of 89 feet (27 m).
Eventually, Dillon sold out to John Keegan with the agreement that the beach would always be named Dillon Beach. Keegan plated the town, built the hotel which still stands as the store and restaurant (built of first growth redwoods). Keegan also built cottages, one of which still stands along the road to the beach. Keegan ran a stage coach from Dillon Beach to Tomales where it met the train. Keegan eventually sold the holdings to the Lawson family who owned it until the arrival of the Clines. The first post office at Dillon Beach opened in 1922. During the 1960s, Oceana Marin was developed north of town by John Keegan's grandson, James Keegan of Wells Fargo Bank and Henry Trione of Sonoma County Mortgage. Fancy modern coastal houses were built on the hillsides overlooking the quaint town of small cottages giving it a unique appeal.