(California)
Guadalupe-Nipomo Dunes is the largest remaining dune system south of San Francisco and the second largest in the U.S. state of California. It encompasses an 18-mile (29 km) stretch of coastline on the Central Coast of California and extends from southern San Luis Obispo County to northern Santa Barbara County. (Ref: https://en.wikipedia.org/wiki/Guadalupe-Nipomo_Dunes)