Helensburgh, a Victorian spa town in Argyll and Bute

Before present-day Helensburgh existed the area was known as Millig and was owned by de MacAulay clan. They built a stronghold called Ardencaple on higher ground overlooking the Clyde estuary during the twelfth century. Recorded in 1351 as Airdendgappil the name is said to be derived from the Gaelic Ard na gCapull meaning "cape of the horses". The Lairds of Ardincaple saw their fortunes turned in the eighteenth century and were forced to sell of their land piece by piece. The Ardincaple Estate was purchased by John Campbell, 4th Duke of Argyll around 1764. He and his successor employed the famous architect Robert Adam to execute an extensive remodelling of the castle. After the death of the eighth duke in 1823 the Duchess dowager sold the entire estate to the Colquhouns of Luss in 1852.

Sir James Colquhoun had bought the estate to develop it from a rural area with a castle and a small fishing port (at the village of Rhu) into an industrious urban settlement. Part of his plan was the construction of a new town, which he named Helensburgh after his wife lady Helen Sutherland. This new town of Helensburgh was situated about 20 miles northwest of Glasgow on the northern shore of the deep Clyde estuary. Colquhoun first built a port believing his new industrial settlement would benefit from well organised port services. The result of his ferry service across the Firth of Clyde was that the residents of existing industrial towns near the Port of Glasgow such as Greenock took up residence on the more attractive northern shore and commuted to work by crossing the estuary. This success as a dormitory town was further increased by improvements in transport links. First there was the arrival of the railway to Glasgow in 1858. This was followed by the ocean steamer invented by Henry Bell that ferried day trippers and cargo along the estuary from Glasgow and back. In 1894 a railway extension was completed that passed to the north of the town and connected Glasgow with northern towns like Fort William and Oban via Helensburgh.

The new town of Helensburgh was laid out as a grid of streets behind a seaside promenade that followed the gentle curve of the shore. This promenade forms a T with the main route north towards Luss. Two winding streams were incorporated into the grid unaltered. In time parts of these streams was culverted, for instance Milligs Burn now flows underneath Helensburgh Central station in a brick tunnel. The grid plan was inspired by the plans for Edinburgh's New Town (built between 1765 and 1850), although the expansion of nearby Glasgow is also characterised by several grid systems. Only the central parcels around the station and Colquhoun Square have been fully developed with urban buildings, the rest of the grid parcels were filled with large and medium size houses in gardens. This in combination with the wide streets planted with trees gave Helensburgh the appearance of a "suburban colony".

This plan of Helensburgh before WW2 shows the grid that was in part altered to accommodate the small rivers Glenns Burn (g) and Milligs Burn (m). These grid adaptations created room for the Hermitage Park (H), the Eastend Public Park (E) and the cemetery (C). Within the grid a central public space was created as Colquhoun Square (S). In the west Ardencaple Castle (A) once stood. To the north Blachhill Plantation (B) was planted with the reservoirs (R) directly beyond along Milligs Burn. The town has no formal arrangement of public buildings and community services. Helensburgh Central Station (1) penetrates the grid from the east. The ferry terminal (2) lies beyond the grid, but close to the central square. The main church (3) of St Andrew's Kirk occupies one corner of this public space. Between the station and the main park Victoria Halls (4) stand: the Town Hall. Helensburgh Upper Station (5) is situated along the informal axis of the town (Colquhoun Street). Even further up the hill side, on the edge of the plantation, the Hill House (6) was erected. On the edges some alterations to the strict grid layout were made after 1900. This is most evident in a garden village type neighbourhood (G) that sits between Old Luss Road and the railway.

Within the new town provisions were made for parks and recreational spaces. A golf course was built to the north of the town. Blackhill Plantation was planted to separate the town from the windy heathland beyond. Ardencaple Castle was converted into a spa. Directly north of the railway station part of the grid was not executed to accommodate Hermitage Park on either side of Milligs Burn. Along this small river several reservoirs were created over time to provide the inhabitants with drinking water. After 1900 the town expanded within the confines of the new railway with typical houses along curved streets as was the norm in garden city style developments. It is in this period that Helensburgh most famous building Hill House by Rennie Macintosh was built. The older parts of the town are a typically Victorian mix of revival architecture styles with a strong emphasis on neo-classical stone buildings.

Helensburg in the 1930's shows an expanded grid with new features such as cul-de-sacs, curved streets and crescents. The town still sits between the dry valley of Woodend and the 1894 railway to Fort William. The main grid is shown in red. The central portion of the grid is made up of squares, the outer sections are both more rectangular. It is clear that the main axes of the grid are the Colquhoun Street and King Street. In the street names Sinclair street, the thoroughfare that runs parallel to the main axis, is the demarcation lane separating the "west streets" from the "east streets" (West King Street - East King Street). After 1950 the town would go beyond these limits and expand via a number of planned housing estates. This expansion of the town was mainly due to the nearby Faslane naval base.