 Throughout the Civil War , the Confederacy maintained a network of underground operators in southern Maryland , particularly Charles and St. Mary 's counties , smuggling recruits across the Potomac River into Virginia and relaying messages for Confederate agents as far north as Canada . Booth recruited his friends Samuel Arnold and Michael O 'Laughlen as accomplices . They met often at the house of Maggie Branson , a known Confederate sympathizer , at 16 North Eutaw Street in Baltimore . He also met with several well @-@ known Confederate sympathizers at The Parker House in Boston . 
