Fallen Leaf Lake is just south of Lacamas Lake, west of Round Lake.  The park has a beach area and large shelter available for reservation for events.  The trails here connect to several others connecting to nearby neighborhoods.  The TrailForks App has this area well mapped.

There are a few spaces for parking at the park entrance.  An alternative is to park on NE 23rd Ave and walk around the Fallen Leaf Softball Field to reach the park trails.