Supple's Marsh came into being along with Lake Winnebago after retreat of a glacial ice sheet that covered this region 10,000 years ago.
The retreating glacier deposited gravel and rocks that blocked ancient northward flowing drainage systems thereby creating a large lake known as Glacial Lake Oshkosh. Centuries later a portion of this lake became Lake Winnebago and its adjacent marshlands.
From that time forward, Supple's Marsh has been a haven for fish and game. Here was where the Winnebago Indian fished and hunted long before the white man appeared. As the years progressed, white hunters and anglers took over, concentrating on the marsh for profit, sport, and food.
On March 25, 1929, Mathias Supple purchased the marsh from the Wisconsin Central Land Co., the holding firm for the Soo Line Railway. The Supple family started a fur farm here in 1932, harvesting as many as 6,000 muskrats in one year.
The City of Fond du Lac acquired the 240 acre marsh from the Supple family in 1967. Hunting and trapping are banned now and Supple's Marsh has become a nature conservancy for all to enjoy.