In the annals of emancipation, Minnesota is recognized as one of the “free states.”

But when author and historian Walt Bachman began digging into his family history, he uncovered substantial evidence that as late as the 1850s, slaves were kept by officers at Fort Snelling and Fort Ridgely, in full knowledge of — and even subsidized by — the government.

When these slaves were sold to civilians, they continued to live in Minnesota under the bonds of slavery, and their children were born into slavery.

“Slavery in the North was not tied to agriculture or industry, as it was in the South. They typically worked as house servants,” said Bachman.

“In Minnesota, there were never large gangs of farm workers, or auction blocks. There weren’t those trappings of the worst forms of slavery,” he said. “But there is ample evidence of brutality towards slaves in Minnesota, including a slave who was whipped to death by her Army officer master. Slavery, wherever it was practiced, was a pernicious institution, and Minnesota was no exception.”...