Lake Sinissippi History


Excerpts from Lake Sinissippi Citizens Handbook- Lake Sinissippi Improvement District


In 1845 John Hustis, the founder of the Village of Hustisford, built a log dam on the river, just south of the Tweedy Street Bridge, with a sawmill at the west end of the dam. This impoundment of the river caused it to spread across the wetland basin, forming the picturesque lake and wooded islands that we see today. The lake was originally called “Cranberry Lake”, and then “Hustisford Mill Pond” and “Lake Hustisford.” Later, the name was changed to “Sinissippi”, from an Algonquin phrase, “sinsepe,” which means “lake-like river.”

Late 1800s

During the period 1850-1870, Lake Sinissippi was an important throughway for the state logging industry. Pine trees from forests north of Oshkosh were taken down the Wolf River to Lake Winnebago and Fond du Lac, then by railroad to the West Branch of the Rock River. The logs were off loaded into the river, then rafted through the lake and over the dam in Hustisford, to continue their journey all the way to Janesville. Ice making was also an important business from 1855 to 1945. Ice was cut on the lake south of Anthony Island and stored in one of nine icehouses in the village. In 1890 the Hustisford Navigation Company organized to provide steamboat service between Hustisford and Horicon. The “Rock River Lilly” held 20 passengers and furnished service to summer residents. Ferry service was also available from the Horicon Road (Highway E) to Anthony Island and from Tweedy Street to Radloff Island from 1880 to 1950. Iceboats were manufactured and sold in Hustisford in the early 1900s. Ice boating was a popular sport at the time. A 48-acre farm was established on Radloff Island in 1876 with complete barn, silo and granary. Later, corn and alfalfa were grown on Anthony Island.


In 1908 the State Supreme Court ruled against the Rock River Valley Land Company of Illinois, which wanted to turn the Horicon Marsh into farm land by removing the Hustisford dam. This action brought an end to this lawsuit that threatened to eliminate the lake. The court declared that because Sinissippi had been a lake for more that 40 years, it had become a natural lake and could not be destroyed. This is the reason for the phrase, “Historic Lake Sinissippi.”


In 1939 a new concrete dam replaced the old wooden dam. The water level was raised 1.4 feet to its present elevation, increasing the lake area to 2,300 acres. The marshy shoreline of the lake was subject to rapid erosion, due to the continuous high water level. Over the past six decades water erosion has caused four of the original 12 islands and shoreland wetlands to disappear, resulting in the present lake area of 2,855 acres. Much of the shoreland of Lake Sinissippi is still beautiful, rolling farmland. The scenic beauty of the lake is also enhanced by the quiet, wooded islands that have been a camper’s paradise since the 1960s. In 1978 the Sinissippi Ski Club was organized by local water ski enthusiasts. Water ski shows and boat parades have been popular lake events in recent years.


Given the gentle contours of the flooded land, Lake Sinissippi is a very shallow lake, averaging four feet for most of its area, with a maximum depth in a few places of eight feet. Upstream from Sinissippi, the Rock River watershed (i.e., the area that drains into the river) includes the Horicon Marsh as well as thousands of acres of agricultural land. The total watershed of the lake is over 500 square miles. Lake Sinissippi’s physical location at the bottom of this large watershed is a key factor associated with the problems in maintaining water quality. During snow melt and heavy rain, runoff from agricultural fields makes its way into Sinissippi with the Rock River water, and from several small streams in the
lands surrounding the lake. Agricultural runoff brings silt and nutrients to the lake, contributing to the growth of algae, increasing water turbidity and resulting in a gradual filling of the lake bottom. Other pollutants reach the lake from upstream urban runoff, wastewater treatment plants, failed septic systems, boating spills and runoff from lakefront properties–landscaping fertilizers and weedkillers, soil and sand from building sites, organic waste, and other substances that we fail to contain within our own properties. Environmental experts call the water quality condition of Lake Sinissippi “eutrophic”. This means that its water is enriched with nutrients such as phosphorus and nitrogen, is turbid and has reduced oxygen content. Eutrophic lakes favor the growth of water-borne algae rather than root-based plants. Game fish require clear water, because they feed by sight, and root-based aquatic weeds for cover. Carp and bullhead, by contrast, thrive in turbid, murky water and hasten the process of eutrophication by uprooting plants and stirring up sediment.
Recreational use of Lake Sinissippi includes boating and water-skiing, hunting, bird watching, snowmobiling and enjoyment of the scenic beauty. The lake shores and water are home to a rich and diverse bird population, including bald eagles, wild turkey, sandhill cranes, heron, egret, mallard and white pelicans. River otter, muskrat and various amphibian and reptilian species find refuge in the wetlands and riparian habitat of the lake.

Lake Sinissippi Association

In the 1940’s, a group of lake residents shared a common vision of lake protection and enhancement of the lake community. The Lake Sinissippi Association was established in 1944 as a volunteer property owner’s association.
The Wisconsin Department of Natural Resources and the Lake Sinissippi Association conducted a major lake rehabilitation project in 1972. The project involved lowering the lake level to eradicate carp in the lake and Rock River headwaters. The project was only moderately successful, however. The extended lake draw down created a condition in which growth of aquatic weeds proliferated. Fish stocking programs and an aeration system to minimize winterkill were initiated in the 1980s, but the lake environment did not provide suitable habitat for a sustained game fishery. The Association also conducted a series of lake studies to provide important technical data needed for lake management decisions. The Association is active in a number of public educational programs and lake improvement projects to help meet the needs of Lake Sinissippi. Recently LSA has bee involved in improvements Safety Buoys, Fish Stocking, Rock relocation, Carp removal Via Commercial Fishing, Community Education, and sponsoring the annual Lakefest July 4th event.

Lake Sinissippi Coalition

In 1997, the Association joined with other interest groups and local government officials to form the Lake Sinissippi Coalition. The Coalition identified major issues of lake improvement:
• Situation – sediment and polluted runoff entering the lake
• Aquatic Ecology – vegetation, fish species and diversity and water quality
• Wetlands and Shoreland Use
• Lake Management

Lake Sinissippi Improvement District

The recommendations and issues identified by the Coalition became the organizing principles for the formation of the Lake Sinissippi Improvement District in 2000. The Lake District is a statutory unit of local government with responsibility to protect and rehabilitate Lake Sinissippi. Management of the Lake District is by a board of commissioners elected by District residents and property owners. The Lake District’s operational focus is on major lake rehabilitation projects. The Lake District, in conjunction with the Association, also provides information to residents to assist in lake improvement efforts.