| Number | County | Town | Size | Built | Verif | GPS | Description |
| CT-01-01 | Fairfield | Bridgeport | 1856 | In Bridgeport. At the corner of Burnum St. & 223 Harriet St. Barnum-Suhren octagon house, 2 story, grout construction, porch encircles both stories, windowed cupola w/flat roof. Built for P.T. Barnum by Nathan Gould. (N41 11.232 W73 11.118) | |||
| CT-01-02 | Danbury | 1852 | In Danbury. At 21 spring St. Octagon house, 3 story, grout construction with walls about 12" thick. An elaborately decorated porch encircles the house on the second and third floors. Now an apartment building. (N41 23.699 W73 27.544) | ||||
| CT-01-03 | Greenwich | 1850s | GONE | In Greenwich. On Millibank Av. Octagon, removed to make room for the Greenwich hospital. | |||
| CT-01-04 | Greenwich | 1850s | GONE | In Greenwich. 513 Steamboat Rd. Wellstood-Hansen, octagon house. Razed 1960. | |||
| CT-01-05 | Stamford | 1890s | GONE | Octagon house at 120 Strawberry Hill Av. Burned 1985. | |||
| CT-01-06 | Bridgeport | 2001 | 09-2006 | --GONE-- N41 10.39 W73 11.25 | In Bridgeport. On the SE side of I95 at exit 27 at 600 Main St. Arena at Harbor Yard, oval bldg. | ||
| CT-01-07 | Wilton | 70' | 1968 | N. of Wilton, Wilton Township. CT33 (Ridgefield Rd.) NW 1.6 miles from jct with CT106 (Belden Hill Rd.) in Wilton, N. (right) on Nod Hill Rd. 0.2 miles, NE (right) on Olmstead Hill Rd. 0.6 miles to the house on the N. side of the road at 122. Michael Von Oehsen, true round rotating house. Built by Richard Foster. (N41 13.054 W73 26.947) | |||
| CT-01-08 | Westport | c1847 | In Westport. Museum of Westport History, heptagonal barn, cobblestone, octagon roof, no cupola. (N41 08.683 W73 21.671) | ||||
| CT-01-09 | Westport | In Westport. Westport Historical Society, octagon bldg. (N41 08.680 W73 21.659) | |||||
| CT-02-01 | Hartford | East Hartford | 1858 | In East Hartford. At 159 Naubric St. Hollister, octagon house, 2-story, solid exterior walls made of 1x5 & 1x4 boards laid flat and nailed together. The 4 and 5 inch boards were laid alternatively to provide grooves 1 inch wide and ½ inch deep on each side to hold the plaster which was applied directly to the wall on the interior. The exterior walls are covered with clapboard. Flat roof, no cupola. (N41 43.817 W72 37.724) | |||
| CT-02-02 | Rocky Hill | 09-2006 | N41 39.116 W72 39.410 | In Dinosaur State Park SW of Rocky Hill, Rocky Hill Township. CT99 (Main St.) S. 0.7 miles from jct with CT160 (Elm St.) in Rocky Hill, W. on CT411 (West St.) 0.9 miles to the park on the S. side of the road. 5 sided bldg, geodesic roof. | |||
| CT-02-03 | Hartford | 1914 | 07-2024 | N41 45.908 W72 40.757 | In Bushnell Park in Hartford. On the E. side of Trinity St. 380' S. of Jewell St. Carousel, 22 sides, cupola. | ||
| CT-02-04 | Hartford | 07-2024 | N41 45.901 W72 40.740 | In Bushnell Park in Hartford. On the E. side of Trinity St. 380' S. of Jewell St., just E. of the carousel. Carousel Annex, 12 sides. | |||
| CT-02-05 | Hartford | 07-2024 | N41 45.504 W72 40.122 | CT-02-05) in Hartford, Hartford County, CT. On the S. side of Charter Oak Av. 200' E. of Wyllys St. CREC, hexagon bldg, cupola on top of a cupola. | |||
| CT-02-06 | Hartford | 07-2024 | N41 45.998 W72 40.403 | In Hartford. At the NW corner of As;ylum & Main Sts. Octagon bldg. | |||
| CT-03-01 | Litchfield | Woodbury | S. of Woodbury on US6 near the Woodbury Southbury township line. Octagon barn, large frame with a cupola. The exterior walls are covered with vertical boards. Surrounded by too many trees to get a good photo. (N41 30.531 W73 12.356) | ||||
| CT-03-02 | New Milford | Octagon building along US7, between New Milford & Brookfield. Has been a display room and a store. It is located near a golf course where it is now used as a storage room. (N41 31.756 W73 25.377) | |||||
| CT-03-03 | Washington | 1850 | ? | 216 Nettleton Hollow Rd. Nettleton-Dorr octagon house located on Nettleton Hollow Rd., off CT47. It is covered with asbestos shingles. The house is hidden behind a great deal of overgrowth and trees, and is hard to see or photograph. | |||
| CT-03-04 | Washington Depot | 1865 | ? | Octagon house. Take the road directly across from the Dorr house (CT-03-03) and go up the hill. At the top, take the blacktop to the right. | |||
| CT-03-05 | New Milford | 09-2005 | --GONE-- N41 33.09 W73 25.08 | S. of New Milford, New Milford Township. US7/202 S. 1.7 miles from jct with US7 & US202 (Bridge St.) just W. of New Milford to the bldg on the W. side of the road. Union Savings, octagon bldg, brick, cupola sculpted into roof. | |||
| CT-03-06 | Washington | 1866 | E. of Washington, Washington Township. Solley, octagon house, low pitch roof, central chimney. Built by Simeon H. Calhoun. (N41 37.761 W73 17.193) | ||||
| CT-03-?1 | Washington | S. of Washington, Washington Township. 25 Painter Ridge Rd. Nancy Steinman, round house (HGTV). (N41 36.999 W73 18.056) | |||||
| CT-04-01 | Middlesex | Cromwell | 31' | 1858 | N. of Cromwell. 33 Prospect Hill Rd. CT99 N. from Cromwell to the Seminary. Octagon house, 3-story, exterior is of grout. (N41 36.408 W72 38.875) | ||
| CT-04-02 | Portland | 1853 | In Portland. At 26 Marlborough St. Joseph Williams, octagon house, built of brownstone. (N41 34.335 W72 38.241) | ||||
| CT-04-03 | Portland | 1855 | In Portland. At 28 Marlborough St. Gilbert Stancliff, octagon house. (N41 34.326 W72 38.219) | ||||
| CT-04-04 | East Hampton | 1862 | In East Hampton. At 6 Middletown Av. Deming Sexton, octagon house, 3-story, but from the front it is only 2 stories. The walls are built of bricks and concrete and covered with stucco. The wide projecting cornice is supported at each angle by a large bracket. (N41 33.993 W72 29.945) | ||||
| CT-04-05 | East Hampton | 1855 | In East Hampton. On Bevin Blvd. An L has been added, but this doesn't take away from the octagon appearance. Henry Smith, octagon house, 15" concrete walls. (N41 34.870 W72 30.211) | ||||
| CT-04-06 | Cobalt | 1857/73 | In Cobalt. At 11 Old Middletown Rd. William T. Tibbals octagon house. (N41 33.788 W72 33.287) | ||||
| CT-05-01 | New Haven | Guilford | 1856 | In Guilford. At 84 Fair St. Leete Griswold octagon house, 2 story, flat roof, windowed cupola. Built by Edwin A. Leete. (N41 17.216 W72 41.137) | |||
| CT-05-02 | Meriden | 1898 | GONE | In Meriden. At 30 Franklin St. Octagon. Demolished in 1970 to make room for a new highway. | |||
| CT-05-03 | New Haven | 1850s | GONE | In New Haven. Located at the NW corner of Temple & Grove Sts. Octagon. | |||
| CT-05-04 | New Haven | 1875-7 | In New Haven. At 66 Hallock St. Octagon house, 1 ½ stories. (N41 17.995 W72 56.315) | ||||
| CT-05-05 | Wallingford | 1857 | N. of Wallingford, Wallingford Township. At 37 New Place St. Octagon house, 2-story. (N41 29.372 W72 49.406) | ||||
| CT-05-06 | Wallingford | 1856 | N. of Wallingford, Wallingford Township. Octagon house, 2-story. (N41 29.398 W72 49.398) | ||||
| CT-06-01 | New London | Mystic | 1850 | 2000 | N41 21.081 W71 58.671 | In Mystic. W Mystic Av. S. 1.5 blocks from jct with US1 in Mystic to the house at 8. Octagon house, 2-story, white, flat roof, large windowed cupola w/flat roof, porch around front half. | |
| CT-06-02 | West Mystic | GONE | An octagon house built for a retired sea captain has been torn down. | ||||
| CT-06-03 | New London | 07-2009 | N41 20.369 W72 05.980 | In New London. US1 S. 1.6 miles from jct with I95 exit 83, NE (left) on Bank St. 0.2 miles, SE (right) on Shaw St. 0.6 miles, S. (right) on Pequot Av. 0.2 miles to the bldg on the W. side of the road. Pfizer Kids Bright Horizons Family Center, round bldg. | |||
| CT-06-04 | Mystic | 07-2009 | N41 22.418 W71 57.246 | At the Mystic Aquarium & Institute in Mystic. CT27 (Greenmanville Av.) S. 0.2 miles from jct with I95 exit 90, E. on Coogan Blvd 0.35 miles to the bldg on the N. side of the road at 55. Mystic Aquarium, true round bldg, flat roof. | |||
| CT-06-05 | Norwich | 1970s | 07-2024 | N41 31.421 W72 04.618 | In Norwich. At the W. corner of Water St. & Chelsea Harbor Dr. Octagon bldg. | ||
| CT-06-?1 | Norwich | W. of Norwich, Norwich Township. CT82 (Salem Tpke) NE 0.2 miles from jct with I395 exit 80 on the W. side of Norwich, NW on Wawecus Hill Rd. 0.9 miles, E. on Lost Acres Rd. 0.15 miles to the house on the N. side of the road. Geodesic house. (N41 31.330 W72 07.427) | |||||
| CT-07-01 | Tolland | Willimantic | 06-2004 | N41 43.133 W72 16.816 | W. of Willimantic, Columbia Township. CT66 W. 2.7 miles from jct with PA32 (Main St.) on the W. side of Willimantic to the bldg on the S. side of the road at the jct with US6. 10 sided bldg, used car dealership, each side has a garage door, tall windowed & louvered cupola w/ornate roof. | ||
| CT-07-02 | Rockville | 72' | 1939 | S. of Rockville, Vernon Township. Tower on Fox Hill, observation, octagon tower. (N41 51.792 W72 26.656) |