Craignethan Castle is a ruined castle in South Lanarkshire, Scotland. It is located above the River Nethan, a tributary of the River Clyde, at NS816464. The castle is two miles west of the village of Crossford, and 4.5 miles north-west of Lanark. Built in the first half of the 16th century, Craignethan is recognised as an excellent early example of a sophisticated artillery fortification, although its defences were never fully tested.

James Hamilton of Bothwellhaugh and Woodhouselee was a Scottish supporter of Mary, Queen of Scots, who assassinated James Stewart, 1st Earl of Moray, Regent of Scotland, in January 1570. He shot Moray from the steps of his uncle Archbishop John Hamilton's house in Linlithgow.