
Glen Lyon (Scottish Gaelic:Gleann Lìomhann) is aglen in thePerth and Kinross region ofScotland. It is the longest enclosed glen in Scotland and runs for 34 miles (55 kilometres) fromLoch Lyon in the west to the village ofFortingall in the east.
This glen was also known asAn Crom Ghleann ("The Bent Glen"). The land given over to the MacGregors wasAn Tòiseachd. It forms part of theLoch Rannoch and Glen Lyon National Scenic Area, one of forty such areas in Scotland, which are defined so as to identify areas of exceptional scenery and to ensure its protection from inappropriate development by restricting certain forms of development.[1] SirWalter Scott described Glen Lyon as the "longest, loneliest and loveliest glen in Scotland".[2] Apart from a few scattered farms and cottages throughout the glen, the only real settlements are atFortingall andBridge of Balgie.
The glen contains several small hamlets and has a primary school where Gaelic is taught weekly.

Quite densely inhabited from prehistoric times (as many archaeological sites attest), although its present population is of modest size, the glen has been home to manyScottish clans, includingClan MacGregor,[3] Lyon, Menzies, Stewart, Macnaughtan, MacGibbon and the Campbell lairds of Glen Lyon.
At the end of the 11th century the de Leons (later shortened to "Lyon") had come north withPrince Edgar, son ofMalcolm III of Scotland to fight against his uncle,Donald Bane. Edgar was victorious and the de Leons received lands that were later called Glen Lyon in Perthshire.[4][5][6][7] LocalTacksmanRobert Campbell of Glenlyon (1630–1696), led the troops of theEarl of Argyll's Regiment of Foot during their involvement in theinfamous massacre of theMacDonalds atGlencoe in 1691. A magnificent silver-giltbrooch set with precious stones belonging to the Campbell lairds of Glen Lyon (that has been dated to the early 16th century) is currently in theBritish Museum.[8]
Glen Lyon, also written Glenlyon, has been the home of (among others)early Christianmonks (includingAdomnán [locally Eonán] (died 704), Abbot ofIona andbiographer ofSt Columba). It contains at least twocastles:Meggernie Castle [still inhabited] and Carnbane Castle [ruined].[9]
Their history is described in Alexander Stewart'sA Highland Parish (1928), and Duncan Campbell'sThe Lairds of Glenlyon (1886).