Item 85720 - Great Diamond Island Association property, Great Diamond Island, Portland, 1924 Item 85720 - Great Diamond Island Association property, Great Diamond Island, Portland, 1924 Contributed by City of Portland - Planning & Development Item 85720 Zoom 4812px x 3527px - 16.0"w x 11.8"h @ 300dpi | Need a larger size? *Credit line must read: Collections of City of Portland - Planning & Development Image Info Wharf & Waiting Room at Great Diamond Island in Great Diamond Island, Portland, was owned by Great Diamond Island Association in 1924. Casco Bay Lines Show Details