Foss Lake

Located in the northeastern portion of Oceanside, along Douglas Drive, lies a very sensitive and unique wetland habitat called Foss Lake. Approximately 75 acres in size, Foss Lake is one of the only inland alkali marshes in San Diego County.

Over the years, Foss Lake has been altered in various ways. Approximately 50 years ago the area was filled and used as an agricultural site supporting crops and cattle. Recently, the construction of Douglas Drive has divided Foss Lake into two sections, a parcel north of Douglas Drive and a parcel south of Douglas Drive. The southern parcel is undergoing a habitat management project to remove invasive plant species and allow the multitude of sensitive and endangered native vegetation, such as the Diegan coastal sage, pickleweed, and Southern willow scrubs, to flourish.

Foss Lake supports an array of wildlife including the endangered Least Bells Vireo, Yellow-breasted Chat, and threatened California Gnatcatcher.

The Lake has been preserved as an open space biological reserve and is currently under the management of two separate environmental management organizations. The northern portion of Foss Lake is under the management of the Environmental Trust. The southern portion of the Lake is held in trust to the Center for Natural Lands Management. The public may visit the lake, but access is limited to walking. No boating, biking, or motorized vehicles are permitted on the premises.