Tweeddale (Scottish Gaelic: Srath Thuaidh/Tuaidhdail) was one of the four "committee area" or former districts in the Borders Region which existed in Scotland from 1975 to 1996. It is the traditional name for the area drained by the upper reaches of the River Tweed. This area was considered to end before the Yarrow Water flowed into the Tweed, so the area was bounded to the south and east by the Yarrow/Tweed watershed, and to the north and east by the Gala/Tweed watershed. Until 1975 it was named Peeblesshire.
Tweeddale was originally an historic district of Scotland, bordering Teviotdale and the Marches to the east, Liddesdale and Annandale to the south, Clydesdale to the west and Lothian to the north. The district which covered the Sheriffdoms of Peebles and Selkirk later became of the County of Peebles, or Peeblesshire, in the north and County of Selkirk or the "Ettrick Forest" in the south (also known as Selkirkshire), two of the counties of Scotland. The main reorganisation took place during the Local Government (Scotland) Act 1889, this Act established a uniform system of county councils and town councils in Scotland and officially restructured many of Scotland’s counties.