One of the Slate Islands, Seil (Scottish Gaelic: Saoil) is small island on the east side of the Firth of Lorn, 7 miles (11 km) southwest of Oban, in Scotland.
Seil has been linked to the Scottish mainland since 1792 when the Clachan Bridge was built by engineer Robert Mylne. Also known as the Bridge Over the Atlantic, the bridge is still used today and in early summer is covered in fairy foxgloves (Erinus alpinus).
Opinions differ about whether Seil should be counted as an island at all. The Atlantic Bridge or "Bridge Over the Atlantic" mentioned on the signpost links Seil to the mainland. It is more properly known as the Clachan Bridge and was built in 1792/3 for the sum of £450.
The single arch of the bridge is 72ft wide and is steeply humped to provide a clearance above high water of 28ft to avoid obstructing the passage of small vessels. Originally designed to have two arches by John Stevenson of Oban, the plans were amended to the single arch that was built by Robert Mylne.
Seil is an interesting island, and one of remarkable contrasts; plus a history that adds greatly to its fascination. It makes an excellent day out from Oban, and has the added advantage of being one of the few Scottish Islands for which a ferry timetable is not needed.