Leith (lēth) [key], former town, Edinburgh, SE Scotland, on the south shore of the Firth of Forth. It was incorporated into Edinburgh in 1920. As a strategically located port, Leith was the object of contention in several struggles. It was sacked by the English in 1544 and 1547, and Mary of Guise held it for the Catholics against a siege by English and Scottish Protestants in 1559–60. Leith was burned in the Jacobite uprising of 1715.