Madrona Marsh is a forty-three-acre seasonal freshwater wetland in Torrance and one of the few natural areas remaining in the South Bay’s urban landscape. Formed by a depression created as the Palos Verdes Peninsula rose, its shallow basin and vernal pools fill with winter and spring stormwater, then gradually dry by late summer through evaporation, percolation, and transpiration. Reserved for oil production in 1924 but never fully developed, it survived as habitat for birds, reptiles, insects, and small mammals. Restoration has emphasized native plants and wildflowers, while the marsh also serves education and wildlife study through the Audubon Society, El Camino College, and the Madrona Marsh Nature Center.