Helensburgh (ˈhɛlənzbərə; Baile Eilidh) is an affluent coastal town on the north side of the Firth of Clyde in Scotland, situated at the mouth of the Gareloch. Historically in Dunbartonshire, it became part of Argyll and Bute following local government reorganisation in 1996.
Although it has long been known that there are some prehistoric remains in the Helensburgh area, recent fieldwork by the North Clyde Archaeological Society has uncovered more. However the oldest building in the town itself is Ardencaple Castle which was the ancestral home of Clan MacAulay, and the history of which may date back to the twelfth century. Today only one tower of this building remains, the rest having been demolished in 1957–59.
In 1752 Sir James Colquhoun (died 1786), chief of the Clan Colquhoun of Luss, bought the land which was to become Helensburgh; at that time it was known by such names as Malig, Millig or Milligs.
In 1776 he placed an advertisement in a Glasgow newspaper seeking to feu the land, and in particular he stated that "bonnet makers, stocking, linen and woolen weavers will meet with encouragement". However his efforts were unsuccessful, partly because roads were rudimentary and also because the shore at Helensburgh made it unattractive to shipping – it was shallow, dotted with large rocks and subject to a prevailing onshore wind.
No precise date is known for the change of name to Helensburgh. However it was probably around 1785 when Sir James decided to name the town after his wife, Lady Helen Sutherland (1717–1791); she was the granddaughter of the 16th Earl of Sutherland. However, for a few years both the old and new names for the town were in use and it was also known for a time simply as the New Town. The town's coat of arms is based on those of the Colquhouns and the Sutherlands.
Helensburgh received its burgh charter from King George III in 1802. This was somewhat surprising, as the 1799 Statistical Account of Scotland indicates that Helensburgh only had a population of about 100 at that time.