Home to financier John J. Raskob's brother, William (see Archmere, BR4), the Colonial Revival house is centered on a conservatory and contains a rare Aeolian organ, its 2,400 pipes extending from thirty feet below ground level to the attic three floors above. The announcement party for the engagement of actress Grace Kelly to Prince Rainier of Monaco was held here, as the Kellys and Raskobs were friends, and the bricks for Irisbrook are said to have come from the Kellys' company in Philadelphia. The building now houses the Raskob Foundation for Catholic Activities. Across Kennett Pike to the south is a Colonial Revival hospital (1954–1955) donated by Eugene du Pont of Owl's Nest (CH5); it stands on the site of Pelleport, the William du Pont house, built by architect Theophilus P. Chandler Jr., in Queen Anne Style in the 1870s and demolished in 1954. William du Pont abandoned it for the historic house Montpelier, Virginia. A granite stables survives at Pelleport.