Billie Jo Boehmke remembers the hatch door in her sister Jennie's second-floor bedroom closet. "She kept her shoes there," Billie said, "but if you moved them over and opened the hidden door, it led to a little staircase."

Not that anyone ever ventured into the darkness below. The sisters, their brother and parents moved into the massive stone house on High Street in 1986 on the banks of Rush Creek in the southeastern Minnesota town of Rushford.

When the creek flooded in 2007, the old house suffered extensive damage. That's when the contractor hired to gut the place unearthed a 16-by-30-foot room below the kitchen — accessible only through that hidden door in the closet.

Researchers determined that the original owners, Hiram Walker and Roswell Valentine, were more than town founders behind Rushford's first flour and saw mills in the 1850s. They were also Quakers who maintained the secret room to help escaped slaves fleeing to Canada along the series of clandestine stations and safe houses known as the Underground Railroad.

That room was lost in the remodeling eight years ago. Which shows how tricky it is for historians to find traces of the Underground Railroad in Minnesota. Few of those involved in the network kept written records, fearing that such evidence could jeopardize the lives of the slaves, their allies and the operation credited with helping more than 100,000 slaves nationally on their scramble north toward freedom.

Minnesota was largely anti-slavery territory, but that didn't stop Southerners — with slaves in tow — who flocked to the state's healing natural springs and cooler climate in the summer. Fugitive slave laws required runaways to be returned to their owners — whose money spent at hotels in St. Paul, Minneapolis and St. Anthony bolstered the early state economy.

With riverboats the major mode of travel, vestiges of the Underground Railroad can be found along the Mississippi River corridor, according to geologist and history buff Jeffrey Broberg.

Sixteen miles south of the Winona riverboat dock, and 5 miles north of Rushford, Broberg met Dan Ziebell, who grew up on a farm near Hart, Minn. He recalled a rough trail running through the property. Everyone called it the Slave Road. Stone retaining walls and hitching posts remain.

Ziebell said a neighbor's barn, with a stone foundation, also included a secret room to harbor fugitives — accessible only through a hayloft hatch. That barn is gone, and the road was renamed Whiskey Road, after bootleggers in the 1920s began traveling the route once used by escaped slaves.

One of the most detailed reminiscences of Minnesota's role in the Underground Railroad came in 1895 — three decades after slavery ended. A 63-year-old black man named Joseph Farr, surrounded by his family, invited a St. Paul reporter into his parlor.

"He greatly regrets not having preserved the memoirs of the affairs that took place while the 'underground' was in operation," the reporter wrote in the Pioneer Press on May 5, 1895.

Farr's regrets were unwarranted. His stories are golden. Born in 1832 in Washington, D.C., Farr worked as a cabin boy on a steamboat churning between Galena, Ill., and the Minnesota frontier.

At 18, he moved to St. Paul to work for his uncle, a popular fiddling barber named William Taylor. He lived across 3rd Street from his barber shop, which stood next to the post office on what is now Kellogg Boulevard.

Taylor was a pivotal leader in St. Paul's black community, which at the time numbered only about 60 people. He was killed on the first day of the U.S.-Dakota War in 1862. Accompanying government messengers carrying late gold annuity payments, Taylor planned to cut Dakota men's hair at the Lower Sioux Agency when he was fatally shot.

Back then, the Underground Railroad was loosely organized. Said Farr to the Pioneer Press: "There was no society or anything of that kind, but we were doing whatever we could."

The network, he said, included a black steamboat porter in Galena who came up with "all kind of schemes" to separate slaves from their owners and sneak them on to riverboats.

Upon arriving in St. Paul, the fugitive would be shuttled to Taylor's house. On a summer day in 1852, one slave showed up "much better dressed than was common with colored people at that time," Farr recalled.

The slave "sat down and begun to cry at a tremendous rate," he said. Turned out, he added, the "young fellow was a girl" whose cross-dress disguise, suggested by the porter in Galena, helped her elude her owner and others giving chase.

"She was young and fine looking and would probably be worth a couple thousands dollars in the South," Farr said in the article, "so it was a sure thing that there would be a great effort made to find her."

The fugitive's owner showed up in St. Paul the next day at Taylor's barber shop: "I lost a girl and I am going to have her back," he said. "Find her for me and it will be worth $30 for you."

Taylor ignored the bribe but kept him talking while one of his regulars slipped out, crossed the street and shooed the fugitive from the windowsill perch where she sat.

"Fortunately her master didn't look that direction and went away satisfied" that Taylor would find her. Instead, they dressed her again as a man, and put her in a buggy bound for White Bear Lake.

A sympathetic Frenchman harbored the woman in the woods for a few weeks. "They made a very thorough search for the girl, but never got her," Farr said.

They hustled her to Chicago en route to Canada. She wrote Taylor a letter a few months later, saying she was safe.

"Oh, I can't tell how many slaves we got away," Farr said, 121 years ago, "but we were so industrious that the slave owners gave up bringing their slaves with them."

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com.