Recent Sand Dunes

Sand dunes above Baker Beach
Sand dunes cap the bluffs above Baker Beach.

Will Elder, NPS

Recent sand dunes cover the Colma Formation and the Franciscan Complex over large areas of San Francisco. These dunes are composed of sand that has blown up and over the hills from Ocean Beach and Baker Beach.

The sand originated on the broad coastal plain of the Sacramento/San Joaquin River system, which extended from the Golden Gate to the Farallon Islands during the last glacial period, when sea level was as much as 300 feet lower than present. Sea level rose rapidly between 10,000 and 5,000 years ago, transporting the sand from this plain onto the beaches, from where it then blew over the coastal hills.

Last updated: February 28, 2015

Park footer

Contact Info

Mailing Address:

Fort Mason, Bldg. 201
San Francisco, CA 94123

Phone:

415-561-4323
Phone is answered daily from 10 am to 5 pm. Leave a message otherwise and we will get back to you. United States Park Police Dispatch: Non-Emergency: 415-561-5505 Emergency: 415-561-5656

Contact Us