Marquam Nature Park is a 178.25-acre (72.14 ha) park, located in Portland, Oregon, United States. The park was acquired by Portland Parks & Recreation in 1979. It includes part of the Marquam Trail, which connects to the 40-Mile Loop. The natural areas includes many native plant species, including bigleaf maple, Douglas fir, red cedar and western hemlock. The park's entrance features a shelter with interpretive displays and maps. The volunteer organization called Friends of Marquam Nature Park formed in 1968 after neighbors of the park successfully prevented housing development on Marquam Ravine.