LUCIA BAY, an inlet of the Irish Sea, on the S. coast of Scotland, Wigtonshire, so called from the small River Luce which it receives at its head. It divides the county by a broad and deep indentation into two peninsulas, the one terminating in the Mull of Galloway on the W., and the other in Burrow Head on the E. of the bay. It is 19 miles broad at the entrance, 16½ miles long, and about 7 miles broad at the head. Owing to the shifting sands of the bay, it is considered dangerous to navigation.