Item 85784 - Whitney property, Echo Point, Great Diamond Island, Portland, 1924 Item 85784 - Whitney property, Echo Point, Great Diamond Island, Portland, 1924 Contributed by City of Portland - Planning & Development Item 85784 Zoom 4752px x 3398px - 15.8"w x 11.3"h @ 300dpi | Need a larger size? *Credit line must read: Collections of City of Portland - Planning & Development Image Info Summer Dwelling at Echo Point in Great Diamond Island, Portland, was owned by Joseph W. Whitney in 1924. On Echo Point and private wharf Show Details