History of Big Mantrap Lake
About the Lake
Big Mantrap Lake is a lake of biological significance located near Park Rapids, Minnesota.
Nestled in the heart of northern Minnesota, Big Mantrap Lake is a place of remarkable natural beauty, known for its crystal-clear waters, forested shoreline, quiet bays and timeless Northwoods character. Spanning more than 1,600 acres with miles of undeveloped shoreline, the lake offers an exceptional sense of peace, where loons call across the water, wildlife thrives and generations of families gather to reconnect with nature. Recognized for its ecological significance and healthy waters, Big Mantrap Lake reflects a deep commitment to conservation, stewardship and preserving the balance between recreation and the wild beauty that makes this lake so special.
QUICK FACTS
Location: 47°4′18″N • 94°54′48″W
Water Quality: 94%
Size: 1,618 acres
Max Depth: 68 ft
Shoreline: 26+ miles
Watershed: 43.7% protected, 3.7% disturbed
Timeline
Late 1800s
The Origin of “Mantrap”
The lake was named “Mantrap” because its many bays and peninsulas entrapped and baffled travelers and loggers through the wooded country in their endeavors to pass by or around it. The complex shoreline created a natural maze that confused even experienced woodsmen.
1929
Wonewok Conference Center Built
Chicago businessman Fred Nachman created Wonewok, a 180-foot-long pine log lodge with cottages on Big Mantrap Lake. This exclusive property would later become one of the most significant landmarks on the lake, known for its pristine wilderness and limited access.
1955
3M Purchases Wonewok
3M CEO Herbert Buetow authorized the purchase of Wonewok to create a place away from the office where executives could share ideas and dream. The 680-acre property would serve as 3M's exclusive corporate retreat for the next 70 years, maintaining pristine wilderness and extensive trail systems.
1958–present
Always a Muskie Lake; Stocking Different Strains
Muskies have historically been the dominant fish predator in Big Mantrap Lake and the lake has long been managed as a “muskie lake.” Efforts to stock the lake with young muskies and chart their activities have gone on for more than 70 years. The Minnesota DNR stocked strains from Shoepack Lake, near the Canadian border, from 1958 to 1983. That was discontinued because the Shoepack strain didn’t grow large enough to satisfy anglers. In 1987, the DNR stocked a muskie strain from Wisconsin that grew larger. Since then, strains have come from Leech Lake, with 750 fingerlings stocked in the even years. The Leech Lake strain grows large and is used in a statewide stocking program.
2023
3M Puts Wonewok Up for Sale
After 70 years of operation, 3M announced the closure and sale of its 680-acre Wonewok Conference Center as part of corporate restructuring. The property, valued at nearly $15 million, included the historic lodge, cottages, private Petit Lake, and six miles of undeveloped Big Mantrap shoreline.
Today
A Lake Protected and Cherished
Today, Big Mantrap Lake stands as a testament to successful conservation and community stewardship. With 46% of the lake area being 15 feet deep or less, over a third of its 26+ miles of shoreline remaining undeveloped, and its watershed 43.7% protected, the lake maintains excellent ecological health. It serves as the headwaters of the Mantrap Chain of Lakes and continues to provide exceptional muskie, northern pike, bass, and crappie fishing. The new Mantrap Wildlife Management Area promises to preserve wilderness access for future generations while honoring the lake's rich heritage.
Early 1900s
Logging and Lumber Transport
The lake was leveraged to move lumber from the surrounding forests to a railroad spur at Hoist Bay. This era of intensive logging significantly shaped the landscape, leaving behind a much younger forest that would take decades to mature. Historical images from this period show dramatically different shorelines compared to today.
1930s–1940s
Early Resort Development
The early resort era began with establishments like Mantrap Camp, Fremont's Point, Olson’s, Birch Highlands, White Birch Camp, Trails End Resort, and Siman's Resort opening along the shoreline. These resorts catered to vacationers seeking the peace and natural beauty of northern Minnesota's lake country.
1956
Big Mantrap Lake Association Formed
The Big Mantrap Lake Association was established with the mission of protecting and improving the natural resources of Big Mantrap Lake. The association conducts water quality monitoring, AIS monitoring and prevention, loon nesting programs, shoreland restoration and environmental education.
1989
Water Quality Monitoring Begins
Systematic water quality data collection began on Big Mantrap Lake. These studies confirmed the lake's mesotrophic status, characterized by clear water throughout most of summer and excellent recreational opportunities. The lake maintains an average water clarity of 13 feet.
November 2025
Wonewok Retreat Sold
Billion Real Estate Holdings LLC of Sioux Falls, South Dakota, purchased the Wonewok conference center, facilities and about 155 acres of land from 3M in November 2025 for $4 million. The purchase included the historic lodge, built in 1929, as well as cottages, guest rooms, restaurant and recreational facilities on Big Mantrap and Petit lakes.
February 2025
Land Trusts Purchase 431 Acres from 3M
Minnesota Land Trust and Northern Waters Land Trust purchased 431 acres (16 parcels) from 3M for $5.38 million to donate to the Minnesota Department of Natural Resources. The land would become the Mantrap Wildlife Management Area, opening previously exclusive wilderness to the public for hunting, fishing, hiking, and wildlife viewing. the Mantrap WMA opened in June 2026
Sources: Big Mantrap Lake Association, Minnesota DNR, RMB Environmental Laboratories, Hubbard County records, and various historical archives.