Octagon buildings and structures are characterized by an octagonal plan form, whether a perfect geometric octagon or a regular eight-sided polygon with approximately equal sides. The oldest known octagon-shaped building is the Tower of the Winds in Athens, Greece, which was constructed circa 300 B.C. Octagon houses were popularized in the United States in the mid-19th century and there are too many to list here, see instead List of octagon houses. There are also octagonal houses built in other times and cultures. Below is a list of octagonal buildings and structures worldwide, excluding houses and windmills.

Australia

Canada

At least 19 historic octagon houses are known to exist in Canada distributed across 4 eastern provinces. For a list of these houses, See: List of octagon houses. In Canada, the octagon house craze also engendered an octagonal deadhouse phenomenon. This included octagonal deadhouses, pre-burial edifices, built in the mid to late 1800s along Yonge Street in south-central Ontario, from just north of Toronto to Aurora.

China

Egypt

Ethiopia

Germany

Greece

Hungary

India

Iran

Palestine

Italy

Japan

New Zealand

Norway

Portugal

Singapore

Spain

Sri Lanka

Sweden

United Kingdom

United States