Lake Martha Days
- Downtown Osseo, Osseo, WI 54758
- Visit Website
- Dates: 6/19/2026, 6/20/2026, 6/21/2026
Lake Martha Days is a community celebration held on Father’s Day weekend in Osseo in west-central Wisconsin, celebrating Osseo’s Scandinavian heritage. There is plenty of fun and entertainment for adults, teens, children and families.