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Lock & Dam 4

  • Located on Mississippi River mile 752.8 in Alma, Wis.
  • 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

This pool is very large and includes the recreationally-important Lake Pepin. The site has a public observation platform open from dawn until dusk from April to November.
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