Wigtownshire, also known as the County of Wigtown, was one of the 34 traditional counties into which Scotland was divided for administrative purposes. It occupied the western half of the ancient Kingdom of Galloway and comprised the peninsula known as the Rhins of Galloway and the area of The Machars.
Wigtownshire was bordered to the north by South Ayrshire; and to the east by Kirkcudbrightshire. The main settlements were Newton Stewart, Stranraer, Whithorn and Wigtown. Stranraer served as the county town. A tidying up of the map of counties which reduced their number to 33 in 1890 had no effect on Wigtownshire, which as a result remained a county in its own right until reorganisation in 1975 swept all the counties away in favour of 12 regions.
The regions formed in 1975 were the upper tier of a two tier local authority system, and the area which had formed Wigtownshire became part of the region of Dumfries & Galloway. Most regions were divided into a number of district council areas, and Dumfries & Galloway had four of them.
The area that had formed Wigtownshire became most of the Wigtown District of Dumfries & Galloway region, though the district also took in some of what had previously been the traditional county of Kirkcudbrightshire to the east.
Regions disappeared from the scene in a major reorganisation in 1996, being replaced by 32 unitary council areas. What had started out as the traditional county of Wigtownshire is today the western part of the unitary council area of Dumfries & Galloway. For administrative purposes, Dumfries & Galloway continues to be divided into four management areas based on the former districts. As a result, what was Wigtownshire now forms most of the Wigtown management area.