The Shoreline Historical Museum offers a map of North King County that highlights local historic sites. There is an entry for Ronald Bog Park and here's what it says:
Headwaters to the northern part of the Thornton Creek watershed, the ancient peat bog covered several acres of land. Native Americans living in the area picked cranberries there, as did settlers into the 1940s. A small pond formed at certain times of the year, and people reported having skated on it. At one time, a wooden bridge on 175th crossed the north side. The bog was mined for its peat throughout the late 1940s and 1950s. In 1974 the land was purchased by King County and turned into a park, now a City of Shoreline park.
So Ronald Bog was apparently once a cranberry bog! How 'bout that?
Link to: Other blog posts labeled 'Ronald Bog'