| Number | County | Town | Size | Built | Verif | GPS | Description |
| MD-01-01 | Allegany | La Vale | 14' | 1836 | 05-2002 | N39 38.278 W78 51.135 | SW of La Vale. Alt US40 S. (curves W.) 2.7 miles from jct with Long Dr. in La Vale to the building on the S. side of the road. Lavale Toll House, 7 sided, 2 story, brick painted white, conical roof, small closed cupola, excellent condition. Restored 1998. |
| MD-02-?1 | Anne Arundel | Highland Beach | 35' | 1875 | SE of Highland Beach, District 2 Township. Thomas Point Lighthouse, hexagon. (N38 53.938 W76 26.152) | ||
| MD-03-?1 | Baltimore | Baltimore | 250' | At B&O Railroad Museum in Baltimore. At the SW corner of W Pratt & S Poppleton Sts. Railroad roundhouse, 22 sides. The B&O Railroad has converted a large roundhouse into an interesting railroad museum. (N39 17.125 W76 37.957) | |||
| MD-03-?2 | Baltimore | ? | UNK | Round church no location available. Greek Orthodox. | |||
| MD-03-?3 | Baltimore | ? | UNK | Octagon house on MD1. No other location available. Scott residence. | |||
| MD-03-?4 | Worthington | ? | UNK | Octagon house in town, no location available. | |||
| MD-03-?5 | Lutherville | 1856 | In Luthereville. at 1708 Kurtz Av. Octagon house, 3-stories. Built by Rev. William Heilig. (N39 25.602 W76 37.515) | ||||
| MD-03-?6 | Mt. Washington | 1855 | In Baltimore. NE of Smith Av., W. of I83, 0.6 miles N. of I83 exit 10. St. Agnes College Library, octagon bldg. Mt. Washington, octagon house, windowed cupola. (N39 22.159 W76 39.293) | ||||
| MD-03-?7 | Baltimore | 1885 | In Baltimore. 1808 Sulgrave Av. Steve Walker, octagon house, 2 story, brown, dormer on every other roof section, central chimney. (N39 21.970 W76 39.320) | ||||
| MD-03-?8 | Reisterstown | 1849/50 | NE of Reisterstown, District 4 Township. 3915 Piney Grove Rd. Woodburn, octagon house. (N39 30.320 W76 47.152) | ||||
| MD-03-?9 | Baltimore | 1856 | At Baltimore Maritime Museum in Baltimore. Seven Foot Knoll, true round lighthouse building, 1 story, cupola contains the light. Moved from original location to Baltimore Harbor in 1988. Screwpile construction. (N39 17.017 W76 36.321) | ||||
| MD-03-?10 | Baltimore | At Baltimore Maritime Museum in Baltimore. World Trade Center, pentagon bldg. (N39 17.161 W76 36.580) | |||||
| MD-03-?11 | Baltimore | Pair of octagon bldgs. S. side of Dolphin St. & NE of Jordan St. (N39 18.215 W76 37.419) | |||||
| MD-07-01 | Cecil | North East | 07-2006 | N39 27.650 W76 00.276 | S. of North East, District 5 North East Township. MD 272 (Main St. - becomes Turkey Point Rd.) S. 11.5 miles from jct with MD7 (Cecil Av.) in North East to the house on the W. side of the road. 16-sided house, light blue horizontal siding, no cupola. | ||
| MD-10-01 | Frederick | Frederick | 10-2005 | N39 27.311 W77 20.563 | NE of Frederick, Mount Pleasant Township. MD26 E. 3.1 miles from jct with MD355 in Frederick to the barn on the N. side of the road up a driveway 0.2 miles. Glade Valley Farm, octagon barn, concrete walls, tall louvered cupola with weather vane, sectional conical roof, excellent condition. | ||
| MD-10-02 | Point of Rocks | ? | UNK | Octagonal post office building. | |||
| MD-11-01 | Garrett | Friendsville | 05-2000 | approximate N39 40.63 W79 22.56 | At the eastbound I68 rest area NE of Friendsville. I68 NE about 2.5 miles from jct with MD42 (I68 exit 4) in Friendsville to the rest area. Information bldg, 16 sided, tan vertical siding, 2 story. | ||
| MD-11-02 | Friendsville | 05-2000 | N39 40.614 W79 22.494 | Next to MD-11-01. Canteen bldg, octagon, cut limestone. | |||
| MD-11-03 | Friendsville | 05-2000 | N39 40.614 W79 22.478 | Next to MD-11-02. Rest room bldg, octagon, cut limestone, louvered cupola. | |||
| MD-12-01 | Harford | Darlington | 1854 | 02-2009 | N39 39.088 W76 13.159 | NW of Darlington, District 5, Dublin township. US1 (Conowingo Rd.) W. 0.7 miles from jct with MD161 (Main St.) just N. of Darlington to the house on the S. side of the road at 4429. Wildfell octagon house, 2 story, white horizontal siding, front porch around 3 sides, widows walk, rectangular attachment on west side. | |
| MD-12-?1 | Darlington | 1830s | S. of Darlingon, District 2 Township. 3736 Green Spring Rd. Hexagon school, stone. (N39 35.848 W76 11.502) | ||||
| MD-15-01 | Montgomery | Olney | 28' | 1997 | 10-2005 | N39 08.973 W77 01.288 | In Olney. MD108 SE 1.4 miles from jct with MD97 in Olney, E. on MD108 1.3 miles to the bldg on the N. side of the road. Sandy Spring Museum, octagon bldg, brick, windowed cupola [www.sandyspringmuseum.org] |
| MD-16-01 | Prince George's | Cedar Heights | ? | UNK | Round house no location available. (Can't find Cedar Heights in Prince George's County - DJT) | ||
| MD-16-02 | Bowie | 1972 | 10-2005 | N39 00.514 W76 45.850 | E. of Bowie. On the W. side of the jct of MD197 & MD564 on the E. side of Bowie at 8655 Normal School Rd. Geodesic house build from a kit from California. | ||
| MD-20-01 | Talbot | Easton | ca 1881 | 06-1998 | N38 44.001 W76 04.097 | S. of Easton. MD50 S. from Easton to the church on the E. side of the road. Hexagon church, white horizontal siding, conical roof, no cupola, excellent condition. | |
| MD-20-02 | St. Michaels | 1880 | At the Chesapeake Bay Maritime Museum in St. Michaels. Mill St. E. 0.25 miles (to the end) from jct with MD33 in St. Michaels. Hooper Strait Lighthouse, hexagon bldg. (N38 47.252 W76 13.153) | ||||
| MD-20-03 | St. Michaels | 08-2008 | N38 49.095 W76 16.624 | NW of St. Michaels, District 5, Bay Hundred Township. MD33 N. (curves W.) 4.1 miles from jct with Mill St. in St. Michaels to the house on the N. side of the road. Geodesic house, hexagon windowed cupola. | |||
| MD-20-04 | Tighman | 08-2008 | N38 41.171 W76 20.587 | S. of Tighman, District 5, Bay Hundred Township. MD33 S. 2.2 miles from jct with Coopertown Rd. in Tilghman to the house on the E. side of the road. Octagon house, 3 story, no cupola. | |||
| MD-21-01 | Washington | Hancock | 1991 | 06-2010 | N39 42.943 W78 16.872 | W. of Hancock. At the eastbound rest stop on I68 6.0 miles W. of the intersection with I70 at Hancock at MM74. Sideling Hill, octagon bldg. | |
| MD-21-02 | Hagerstown | 03-2022 | N39 38.640 W77 43.447 | In Hagerstown. At the NE corner of Washington & Prospect Sts. | |||
| MD-21-?1 | Hagerstown | In Hagerstown. Octagon bldg. (N39 39.966 W77 43.165) | |||||
| MD-23-?1 | Worcester | Ocean City | In Ocean City. Lighthouse Club, octagon hotel. (N38 22.863 W75 04.267) |