The Longfellow Creek Watershed (pdf) covers 2,685 acres in West Seattle. The creek flows for more than four miles into the West Duwamish Waterway. The upper 4,900 feet of the creek has been diverted into underground pipes and roughly one-third of the total creek flow drains through pipes beneath shopping centers, houses and roads.
The headwaters of Longfellow Creek were historically located in a natural wetland and peat bog in what is now Roxhill Park. The Roxhill bog was recently restored with the completion of the Longfellow Creek Legacy Trail in West Seattle.
Historically, Longfellow Creek contained populations of coho salmon, cutthroat trout and steelhead trout. In 1999, Seattle Public Utilities conducted spawning surveys on Longfellow creek and recorded 60 adult coho salmon. In addition, juvenile rainbow trout and coho salmon were captured during electrofishing surveys in 1999 by Washington Trout. Numerous groups have released coho fry into the creek over the years, but conditions are not optimal for fish due to the development of the area.