After decades of debate, failed legislation, five public meetings and thousands of letters, the federal government has decided to undertake a comprehensive environmental review on how to swap about 50 square miles of state-owned land inside the Boundary Waters Canoe Area with U.S. Forest Service land outside.

Earlier this year, the U.S. Forest Service agreed to buy about two-thirds of the state-owned land inside the wilderness area, about 56,000 acres, and has applied for federal funding to pay for it. The remaining 30,000 acres will be exchanged for federal forest land outside the BWCA, a prospect that has polarized opinions between conservationists and pro-development interests.

The ownership dilemma goes back to 1849, when the U.S. government gave Minnesota 8.3 million acres to pay for schools. Most of the “school trust” land was eventually sold or leased, but 86,000 acres remain inside the BWCA. How to exchange it has long been a source of friction between conservationists who want to protect it, and those who would like use it for logging and mining revenue for the state.

Various compromises have proposed swapping some or all of the land for federal land elsewhere. A 2012 proposal for an acre-for-acre swap passed the U.S. House but never got a vote in the U.S. Senate.

Now the state and U.S. Forest Service have reached a compromise that calls for both a purchase and a land swap. But the forest service has been inundated this year with thousands of letters and packed public hearings about the swap. Conservation groups want ecologically valuable acres protected, while pro-development interests want land with mining and logging potential. Some 20,000 people signed a Change.org petition to oppose the swap unless it included a plan to permanently protect the remaining school trust land.

As a result, the forest service has decided to complete an in-depth environmental impact statement, said spokeswoman Sandy Skrien.

“The interest and response was greater than we anticipated,” she said.

The review will include all the comments made so far, and will rely on an expert panel to define the scope of the review and analyze the environmental issues. The first draft is expected to be completed in early 2016, and the final one will be done in about a year.