| Number | County | Town | Size | Built | Verif | GPS | Description |
| CO-03-01 | Arapahoe | Aurora | ? | 200 S. Chambers (Denver suburb) | |||
| CO-03-02 | Denver | 06-2005 | N39 44.83 W105 01.18 | In Denver. Bryant St. N. 0.1 miles from jct with I25 exit 210 in Denver to the hotel on the W. side of the road at 1975. Red Lion Hotel, round tower. | |||
| CO-03-03 | Denver | 1999 | 06-2005 | N39 44.64 W105 01.22 | In Denver. At the NW corner of I25 & Bus.I70 (CO40 or Colfax Av.). Mile High Stadium, oval bldg, open top. | ||
| CO-03-04 | Denver | 06-2005 | N39 44.72 W104 58.14 | In Denver. Bus.I70 (CO40 or Colfax Av.) E. 2.4 miles from jct with I25 exit 210 in Denver, N. on Franklin St. 0.35 (3 blocks) miles to the hospital on the W. side of the road. St. Joseph Hospital, round tower. | |||
| CO-03-05 | Denver | 06-2005 | N39 44.88 W104 58.10 | In Denver. Bus.I70 (CO40 or Colfax Av.) E. 2.4 miles from jct with I25 exit 210 in Denver, N. on Franklin St. 0.55 (5 blocks) miles to the hospital on the E. side of the road. Presbyterian St. Lukes Medical Center, oval tower. | |||
| CO-20-01 | El Paso | Pikeview | 12-2007 | N. of Pikeview. Interquest Pkwy E. 0.9 miles from jct with I25 exit 153 N. of Pikeview, N. on Voyager Pkwy 0.1 miles to the church on the E. side of the road at 11025. New Life, hexagon church. (N38 59.520 W104 47.727) | |||
| CO-32-01 | Kit Carson | Burlington | In Burlington. W. of 15th St. 0.1 miles N. of US385. 12-sided building used to house a carousel. (N39 18.547 W102 16.243) | ||||
| CO-33-01 | La Plata | Durango | 09-2008 | N37 16.799 W107 56.381 | At Durango Silver Co. W. of Durango. US160 W. 3.6 miles from jct with US550 on the SW side of Durango to the bldg on the N. side of the road. Octagon bldg. | ||
| CO-42-01 | Montezuma | Mancos | The Hogan Trading Post W. of Mancos. US160 SW 1.6 miles from jct with Bus.US160 just W. of Mancos to the bldg on the NW side of the road. Round bldg. (N37 19.941 W108 20.351) | ||||
| CO-42-02 | Mancos | N37 15.458 W108 29.873 | SW of Mancos. US160 W. 5.7 miles from jct with Bus.US160 just W. of Mancos, S. on CO10 (Ruins Rd.) 14.0 miles to the bldg on the left side of the road. Far View Visitor Center, round bldg. | ||||
| CO-49-01 | Pitkin | Snowmass | ? | Located in Gateway Subdivision, there are several modern round houses. Some of them consist of several units, with each round building a separate room and all rooms connected together with hallways. | |||
| CO-49-02 | Snowmass | ? | Situated atop a high bluff, it can be seen from CO82. Octagon house. | ||||
| CO-58-01 | Sedgewick | Julesburg | S. of Julesburg. E. side US385 0.9 miles N. of I76. Round bldg. (N40 58.769 W102 15.310) | ||||
| CO-60-01 | Teller | Cripple Creek | S. of Cripple Creek. Masonic Av. W. 0.45 miles from jct with CO67 in Cripple Creek, S. on C St. 0.25 miles, SW on Thurlow Av. (becomes CR89) 0.3 miles, S. on dirt road 0.35 miles, left branch at Y 0.15 miles to the house on the E. side of the road. Round house. (N38 44.015 W105 11.304) | ||||
| CO-63-01 | Yuma | Laird | 1880 | 01-2009 | N40 04.75 W102 06.19 | In Laird. Campbell Av. S. 0.15 miles from jct with US34 in Laird, continue S. on driveway 250' to the house. Octagon house, stone, 2 story, porch encircles house, widow's walk, rectangular addition to the N. Built by Burton Durward Prentice. 1-22-09: Owned by Caribou Cattle Co., Boulder, CO. |