St. Paul District > Missions > Navigation > Locks & Dams > Lock & Dam 4

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US Army Corps of Engineers

St. Paul District Website

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Hot Info

The observation deck is currently CLOSED.

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Lock & Dam 4

Located on Mississippi River mile 752.8 in Alma, Wisconsin.
Constructed and placed in operation in May, 1935. Last major rehabilitation completed from 1988 to 1994.
Dam consists of a concrete structure 367 feet long with six roller gates and 22 tainter gates. Earth embankment 5,400 feet long.
Lock is 110 feet wide by 600 feet long.
Brochure

Recreation Opportunities

The Lock and Dam 4 observation deck is open.

Lock and Dam 4

Lock & Dam 4, Alma, Wis.

Contact Information

U.S. Army Corps of Engineers
St. Paul District
Lock and Dam No. 4
P.O. Box 325
Alma, WI 54610-4421

(608) 685-4421