Some buildings, such as the Crenshaw House in far southeastern Illinois, are known sites where free blacks were sold into slavery, known as the "Reverse Underground Railroad".
Uzak güneydoğu Illinois'deki Crenshaw House gibi bazı binalar, özgür siyahların köleliğe satıldığı "Ters Yeraltı Demiryolları" olarak bilinen yerlerdir.