Cooke Castle was the fifteen-room, stone summer retreat of Jay Cooke and his extended family. The family occupied the home at least twice each summer for nearly sixty years. Jay Cooke purchased Gibraltar Island in 1864 for $3001. His brother Pitt Cooke of Sandusky, Ohio, oversaw the construction of the castle. Hundreds of guests, soldiers, businessmen, statesmen,and politicians, joined the Cookes during their visits at Gibraltar. When the family was not occupying the island, Jay Cooke offered his home as a retreat for clergy throughout the Midwest. On the occasion of this photograph, Jay's son, Rev. Henry Cooke, wrote "indeed the dear old house where we have had so many happy times always seems like home." The castle was placed on the National Register of Historic Landmarks in 1966 because of the historic prominence of Jay Cooke and the architectural features of the structure. The fifteen-room home encompassed nearly 9,000 square feet of space. The first floor of the four-story tower is a library with two wall-mounted bookcases carved in gothic fashion.