Tenney Lock is the largest of three boat locks on the Yahara River and is located on the eastern shore of Lake Mendota along Sherman Avenue between the City of Madison’s Filene Park and Tenney Beach. The site consists of a breakwall, boathouse and dam/spillway structure. Public restrooms are available during the hours of lock operations, refer to the lock schedule on the Tenney Lock Webpage for Boaters.
The Tenney Park Lock and Dam site is owned and operated by Dane County Parks. The site was part of the overall City of Madison Tenney Park which was designated a City of Madison Landmark on July 10, 1995 and is on the National Register of Historic Places. The first dam was built of earth just south of the current location in 1847 as an early mill and brewery, but was destroyed in a thunderstorm in 1866. The City of Madison purchased the current site in 1896 and constructed the first lock and reconstructed the dam to allow for shallow drafting boats to move between lakes Mendota and Monona through a dredged channel of the river. Prior to this time, the river was a shallow meandering river flowing through wetlands leading to Lake Monona. In 1958, the lock and dam were reconstructed to provide improved navigational access and water control through the river. The Tenney Lock and Dam/Spillway has been maintained and operated by Dane County since 1981, with approximately 10,000 boats passing through annually. The facility was updated in 2006 and 2017. During normal flows the water level in Lake Mendota is maintained at an average height of five feet above the water level of Lake Monona. A Dane County Historical Society Marker has been onsite since 1967.
In 1846 Wisconsin's territorial legislature approved incorporation of Madison Village and construction of a dam at Lake Mendota's outlet with a canal for navigation between Lakes Mendota and Monona.
The first dam was built of earth just south of the current location in 1847 as an early mill and brewery. It was built by Leonard J. Farwell, later a Wisconsin governor. The dam enlarged Lake Mendota and increased its depth. Prior to construction Mendota's water level was only slightly above Monona's. The dam was destroyed in a thunderstorm in 1866. Despite great controversy it was reconstructed.
In 1896 Madison City purchased Tenney Park site, built a boat lock, and used concrete to improve the dam. Controversy rose again in 1900 when riparian owners whose land was flooded sought removal of the dam. Their suit failed in the courts. In 1959, the lock and dam were reconstructed to provide improved navigational access and water control through the river. The Tenney Lock and Dam/Spillway has been maintained and operated by Dane County since 1981, with approximately 10,000 boats passing through annually. The facility was updated in 2006 and 2017. The City of Madison’s Tenney Park was designated a City of Madison Landmark on July 10, 1995 and is on the National Register of Historic Places.
More information can be found on a historical marker at the park or on the City of Madison Tenney Park History webpage.
