| Porphyry Island | |
| Map: | Canada Ontario |
| Location: | Lake Superior |
| Coordinates: | 48.3506°N -88.6358°W |
| Area Ha: | 107 |
| Area Footnotes: | [1] |
| Length Km: | 3 |
| Width Km: | 0.5 |
| Country: | Canada |
| Country Admin Divisions Title: | Province |
| Country Admin Divisions: | Ontario |
| Country Admin Divisions Title 1: | District |
| Country Admin Divisions 1: | Thunder Bay |
| Population: | uninhabited nature reserve |
Porphyry Island is an island in Unorganized Thunder Bay District in northwestern Ontario, Canada.[2] It is the last island in a chain stretching south west of the Black Bay Peninsula in Lake Superior. It is located about 6km (04miles) from Edward Island Provincial Park, 13km (08miles) from Sleeping Giant Provincial Park, 14km (09miles) east of Silver Islet, Ontario, and 42km (26miles) east of the city of Thunder Bay.
The island and nature reserve take their name from the characteristic quartz and feldspar crystals, or porphyries found in the volcanic rocks.
The entire 1070NaN0 island constitutes the Porphyry Island Provincial Park or nature reserve.[3]
The federal government established a lighthouse at Point Porphyry in 1873. This is located at the southwestern tip of the island.[4]