High Quality Content by WIKIPEDIA articles! Inchkeith (from the Scottish Gaelic: Innis Cheith) is an island in the Firth of Forth, Scotland. It is part of Fife. Inchkeith has had a colourful history as a result of its proximity to Edinburgh and strategic location for use as home for a lighthouse and for military purposes defending the Firth of Forth for attack from shipping, and more recently protecting the upstream Forth Road Bridge, and Rosyth Dockyard. Inchkeith has by some accounts has been inhabited (intermittently) for almost 1800 years. Inchkeith is approximately half the size of the Isle of May at the mouth of the Firth, but is higher.