From the City of Folsom Website
The most fun thing about Humbug Willow Creek just might be that you can tell people it is “out by the soy sauce factory,” because that just sounds so absurd. But there is indeed a Kikkoman soy sauce factory, out in Folsom near Sutter Street. And next to this salty & aromatic spot of industry you’ll find the Humbug Willow Creek Parkway. (Coincidentally it is also adjacent to a Sake tasting room (I am not making this up) which begs the question of whether there are nice yellowtail in that creek, and some wasabi plants.)
The park consists of a nice paved bike trail that winds along a marshy area, with nice resting benches and a bevy of wildlife. The area near the soy sauce factory boasts several walking bridges suspended over the creek. The only thing wrong with this trail is that it is very close to the road, including several spots with nothing between the path and the road. However, the winding nature of the path makes it so this is only an issue for a few yards here and there. The abandoned railroads are a nice touch; halfway through our walk we switched to train walking. (Walking along train tracks awakens something in the American soul, doesn’t it? Something of a shared hobo heritage, or shall we say hoboritage.)
I can only imagine that running or biking on this trail would be a great experience. We approached the walking path from the parking lot of the MAXIMUS corporation, off Glenn Drive and Folsom Blvd, and I couldn’t necessarily find a better starting point for the parkway but you might try Parkshore Blvd.
Here is my map of the area.