Historic 3M Land on Mantrap Lake Protected for Conservation and Public Access

The Minnesota Land Trust and Northern Waters Land Trust partnered to protect a portion of the land surrounding the historic 3M retreat center on Big Mantrap Lake in Hubbard County. This conservation achievement ensures that approximately 449 acres of ecologically significant land and over six miles of shoreline will be permanently safeguarded for future generations.

Mantrap Lake is a designated Lake of Outstanding Biological Significance known for its wild rice habitat, pristine water quality, and vital fish and bird populations. It spans 1,618 acres and reaches a depth of 68 feet. Home to loons, muskie, northern pike, bass, and black crappie, the lake and surrounding lands are an important sanctuary for migratory birds and other wildlife.

Left: Common loons; Right: Manoomin (wild rice)

Partners’ Multi-Year Effort Pays Off

This resounding conservation success is the result of a multi-year effort that began when 3M announced the sale of the property in April 2023. Recognizing its ecological importance, Northern Waters Land Trust, Minnesota Land Trust, Minnesota Department of Natural Resources (DNR), the Conservation Fund, and Trust for Public Land came together to explore protection strategies and to collectively work to complete the project.

In May 2023, these partner organizations submitted a letter of intent to 3M, initiating a complex negotiation process that would take nearly two years to finalize. Ultimately, 449 acres of undeveloped land was purchased in March 2025 by Northern Waters Land Trust and Minnesota Land Trust, with the help of the Department of Natural Resources. This project was funded through the state’s Outdoor Heritage Fund, as a part of the Clean Water, Land, and Legacy Amendment, with a matching contribution of Federal funding through the Minnesota Loon Restoration Project.

This is an incredible conservation outcome for the state of Minnesota and especially the communities near Mantrap Lake and the greater Big Sand Watershed.

Big Sand Watershed Closer to 75% Protection

Protecting at least 75% of the land around a lake or river is crucial for maintaining its long-term health, water quality, and ecological balance. When too much land in a watershed is developed or farmed, runoff and pollution increase and the sensitive balance of aquatic ecosystems is disrupted, which can result in algae overgrowth, dead zones, and water that isn’t suitable for swimming, paddling, or fishing.

Adding these 449 protected acres puts the Big Sand Watershed within 10% of reaching its 75% protection goal, a milestone that will further safeguard the region’s abundant fisheries and thriving ecosystems.

“This project really exemplifies the power of forward-thinking land protection strategies,” said Ruurd Schoolderman, Program Manager at the Minnesota Land Trust. “With this acquisition, we are safeguarding an extraordinary landscape that will provide clean water, wildlife habitat, and recreational opportunities for generations to come.”

The Mantrap Lake property brings the Big Sand Watershed to within 10% of its 75% protection goal.

Future Public Access and Broader Conservation Benefits for Minnesota

The land—which was originally acquired by 3M in 1955—will eventually be conveyed to the Minnesota DNR and open to the public. The new Wildlife Management Area (WMA) will be accessible to the public for outdoor recreation like hunting, fishing, and wildlife observation.

“Protecting this property means securing a future where more people can enjoy the beauty of Mantrap Lake while ensuring that critical habitats remain intact,” said Annie Knight, Executive Director of Northern Waters Land Trust.”

Ongoing conservation efforts like this are vital especially as pressures on natural lands and water intensify across Minnesota. Once natural habitat is parceled and developed, it can no longer filter and protect water, prevent flooding and runoff, or sustain the species biodiversity at the heart of thriving ecosystems. In fact, often these ecological benefits are significantly diminished or lost permanently.

“Now more than ever, local land protection programs are critical to ensuring the long-term health of our landscapes,” said Wayne Ostlie, Director of Land Protection at the Minnesota Land Trust. “With so much uncertainty surrounding federal conservation programs, it is up to all of us to champion conservation at the state and local level.”

Landowners Are Part of the 75% Solution

Landowners in the Big Sand Watershed can continue to play a key role in helping reach the 75% protection goal and preserving water quality, wildlife habitat, and the natural heritage of Northern Minnesota. Landowners with over 40 acres of natural land should contact us to learn more about grant funded protection programs as there may be tax advantages or financial incentives available.

This project was made possible with funding from Minnesota’s Outdoor Heritage Fund, as appropriated by the Minnesota State Legislature and recommended by the Lessard Sams Outdoor Heritage Council (LSOHC), with Federal funding through the Minnesota Loon Restoration Project, and by supporters of the Minnesota Land Trust and Northern Waters Land Trust.