In 1859, John Brown took on the fake name of Isaac Smith and rented the farmhouse for $35 in gold from the trustee of Kennedy's estate. Brown, his sons Owens and Oliver, and Lt. Jeremiah Anderson used the farm as a staging area to prepare for their intended October raid on the Harpers Ferry arsenal, located just a few miles away. Abolitionists varied in their approaches to slavery, which included formal anti-slavery organizations, legal and social advocacy, public demonstrations, and militant actions. Brown's vision for a slave insurrection at Harpers Ferry was among the most dramatic.
As the summer progressed, Brown's Provisional Army of the United States arrived one or two at a time until a total of twenty-one men (sixteen white, five black) were hiding in the farmhouse attic. He also assembled a small arsenal of weapons to assault the Harpers Ferry arsenal. His daughter, Annie, and daughter-in-law, Martha, served as cooks and housekeepers for the Provisional Army.
John Brown's raid on the Harpers Ferry arsenal from October 16-18, 1859, did not garner slave support, and instead drew local militia to take back the arsenal in a violent turn of events. His legacy has remained disputed ever since. The Kennedy Farm had been rumored to be John Brown's headquarters and passed through many owners over the year. It was not until 1972 that South Lynn confirmed this was the case after researching in the Maryland and National Archives. It was added to the National Register of Historic Places in 1973 and granted National Landmark status in 1974.
Major restorations have taken place to turn the clock back to John Brown's time. Essentially, the Kennedy farmhouse had to be taken apart and put back together to restore its historic appearance. Today, the Kennedy Farm is owned by the John Brown Historical Foundation and open for tours by appointment.