Clan Johnstone is a Scottish clan associated with the region of Dumfriesshire. The Johnstones held lands in the area, including the estate of Annandale. The family’s history can be traced back to the 12th century. Notable figures from Clan Johnstone include individuals who have made contributions in various fields. One notable figure is James Johnstone, who was a Scottish mathematician and astronomer. He made significant advancements in the field of mathematics and was known for his work on logarithms.