Nenthorn is a parish and hamlet in the south of the historic county of Berwickshire in the Scottish Borders area of Scotland. It is included in the Floors, Makerstoun, Nenthorn and Smailholm Community Council area, which also includes the parishes of Makerstoun and Smailholm. It was included in the former Roxburgh District of Borders Region, by the Local Government (Scotland) Act 1973, from 1975 to 1996.