Saugus Iron Works National Historic Site preserves the cultural and natural history of the first successfully integrated manufacturing facility for the production of cast and wrought iron in North America. The historic structures of the Iron Works are nestled along the banks of the Saugus River, an important natural resource for newly settled families and workers to the area during the 17th century.

The tidally influenced Saugus River is also a principal natural resource for a wide variety of plants, animals, and other organisms that depend on the river, riparian woodlands, and surrounding marshes as an important habitat.

Saugus Iron Works National Historic Site is filled with plant and animal diversity. The site contains over two hundred species of plants, thirty five species of birds, ten species of mammals, four species of reptiles and amphibians, and at least four species of fish. The site also has numerous species of invertebrates, such as insects, spiders, and crustaceans, an important food source for larger wildlife residing along the Saugus River.