Peeblesshire, historic county of southeastern Scotland that forms a triangle between the historic counties of Midlothian (north and northeast), Selkirkshire (east and southeast), Dumfriesshire (south), and Lanarkshire (west). It lies entirely within the Scottish Borders council area.
The remains of numerous hill forts around the burgh of Peebles indicate occupation of Peeblesshire in the early Iron Age, and there are standing stones near the confluence of Lyne Water and the Tweed. The Romans left traces of their military rule in the camp at Lyne, locally known as Randal’s Walls. In medieval times a series of peels (fortified towers) were erected; the best-preserved is that of Neidpath Castle, a 15th-century stronghold of the Frasers just outside the royal burgh of Peebles. The county is closely associated with the legend of Merlin and has provided background and other material for Sir Walter Scott, James Hogg, and other writers. The growth of woolen textile manufacture in the 18th and 19th centuries expanded the economy of Peeblesshire, traditionally an area of livestock raising and forestry.