Madrona Marsh is a small marsh found in the city of Torrance, near the intersection of Madrona and Sepulveda avenues. The marsh is about 50 acres big and consists of a sump which always contains water, a vernal marsh which dries up in the summer, and an upland area. The sump is where water from the city drains. After this happens it is pumped into the marsh. The marsh area consists of willows, cottonwoods, sycamores, bullrushes, cattails, and various other wetland plants, and is in pretty good shape considering it's found in the middle of Torrance. The upland area consists of sandy soil and mostly non-native vegetation. There are various habitat restoration projects there, some of which have been successful, others of which have been thwarted by gophers, wild oats, or other such difficulties. Also found nearby is the grandiose "nature center" built on land which should have been restored, using money that could have bought thousands of seedlings to go into the marsh. Of course, that's how the city works.

Madrona Marsh is very biologically diverse. You can see all kinds of birds in the area including hawks, kestrels, waterfowl, etc. Small mammals, reptiles, and insects are also abundant. And if you're amidst the cattails you almost can't tell you're in the city. So if you're in the South Bay area of Los Angeles and bored, you can go check it out.