| Segontium | |
|---|---|
 | |
  Location in Gwynedd | |
| Founded | CE 77 or 78 |
| Abandoned | CE 4th century |
| Place in the Roman world | |
| Province | Britannia |
| Structure | |
| — Stone structure — | |
| Built | 2nd century |
| — Wood and earth structure — | |
| Built | 1st century |
| Location | |
| Coordinates | 53°08′14″N 4°15′57″W / 53.1373°N 4.2659°W |
| Town | Caernarfon |
| County | Gwynedd |
| Country | Wales |
| Reference | |
| UK-OSNG reference | SH485624 |
| Site notes | |
| Controlled by | Cadw |
| Website | cadw |
 | This article needs additional citations for verification. (July 2022) |
Segontium (Old Welsh: Cair Segeint) is a Roman fort on the outskirts of Caernarfon in Gwynedd, North Wales.