A railway line was constructed from Derry-Londonderry  to Coleraine in 1853 along a dramatic costal route still remarked upon today.  The village of Castlerock joined the tourist economy as a result. The line required two tunnels which were cut through the imposing cliff  at Downhill between 1845 and 1852. These were among the first of the type on the island and were important engineering feats for the time. They are still impressive today.

When the institutional link was broken between the Church of Ireland and the State in 1869, the Church of Ireland received a substantial dowry and embarked upon a substantial building programme. St Patrick’s in Coleraine was rebuilt soon afterwards with a very elegant tower in a detailed gothic style. The site, however, is very ancient. By tradition it is associated with the saint himself who is supposed to have founded a church on the north bank of the Bann. Foundations of a probable fourteenth century church were discovered during renovations in 1994. The foundations of an earlier church were reputedly discovered in the 1880's extending beyond the present chancel.

Opened in 1859, the sandstone town hall is in an Italianate classical style taking pride of place in the centre of the Diamond and replacing an eighteenth century hall on the same site. It reflects the confidence of the town at this point in its history with thriving industry and  an air of prosperity. Like its predecessor the cost of this building was borne by the Honourable the Irish Society - the company set up to develop this settlement during the Ulster Plantation. 

Another important historic building of the period is the former Coleraine courthouse. Built in 1852, it functioned as the town court for 133 years until its closure in 1985. It is built in a reassuring and authoritative classical style with doric columns supporting a projecting pediment from a commanding position at the top of Waterside Street looking down towards the Bann Bridge.

It found new life as a pub after 1985. it closed for a few years following Covid, but  reopened again in 2025 for the same function under new management.

Another institutional building in the gothic style is Coleraine's former Irish Society School. Constructed between 1867 and 1869  it is a picturesque jumble of pitched roofs, cupolas, turrets and tall chimneys set on a triangular portion of  ground between Beresford Road and Terrace Row within the town. Its picturesque character is enhanced by sandstone trims and bands contrasting with the red brickwork of the walls and a few, structurally unesscesary brick and sandstone buttresses. 

Like the former workhouse it was also vacant for many years. In the early 2000's , however, the building was sympathetically converted into unique and charaterful apartments with triple glazed windows (double glazed secondary glazing behind the original single paned windows) and a complementary housing block was built to the rear. A good example of what can be done to maintain an important historic building once its original use has ceased.

As the nineteenth century progressed, architecture took a more varied turn. The Victorians believed that architectural styles should be more freely used and reflect different functions.  Gothic was often selected for churches, alms-houses and educational institutions – like the Coleraine Workhouse (1842). This building on the Mountsandel Road consciously copied the style of medieval alms houses.  They were built to a standard plan across Ireland, with most towns having a similar building. Coleraine was designed for 700 inmates, with  two larger blocks beyond the entrance building which survives today.  This building contained a porter's room and waiting room at the centre with a board room for the Guardians on the first floor. Inmates were separated by sex and accommodated in different wings off the central spine. During the Famine of the late 1840's the roofs were raised over the boys dormitories to accommodate and extra 60 inmates and a 40 bed fever hospital (now gone) was erected to the south side of the building. A graveyard associated with the workhouse was located on the northern side. in line with most other workhouses, it developed into a hospital from 1929 onwards with workhouse functions stopping completely in the 1940's.  The site was vacated in 2003 with only the listed front block of the former workhouse remaining on the site.

After many years of neglect and increasing dereliction, and a catastrophic fire in 2017, new hope was found for the site in 2020 with a planning proposal to develop the site for high quality housing with the restored historic building converted into three apartments at the entrance. However, though the  housing development is now complete no work has begun on the historic building. Rather than a jewel making this a special and unique site, it looks destined to become a problem for the owners of the expensive houses surrounding the now boarded up ruin. Ironically, the  sales website for 'Earl's Gate' emphasises the access to built heritage in the surrounding area- 'A short drive and you’ll be spoilt for choice when it comes to historical and National Trust sites with Mussenden Temple, Dunluce Castle, Portstewart Strand and the Giant’s Causeway all within easy reach' (earls-gate). Let's hope that the proposed conversion of the workhouse building  is commenced and completed soon. In the last few years Enniskillen's similar block has been conserved and incorporated into the South West Regional College and  Derry-Londondery's  has been converted into an expensive dentists. it can be done.

In the 1830’s a number of the leases on the estates of the London Companies across the rural part of the county came to an end, and, rather than let them again, many of the Companies took a direct interest. A period of enhancement followed with Companies competing with each other, to improve conditions and create the most beautiful village (all in the Georgian style- though churches were often built in a classicised Gothic), the Fishmongers invested in Ballykelly, the Grocers in Eglinton, the Drapers in Moneymore and Draperstown, and, in this area, the Mercers invested in Kilrea . They rebuilt many of the town’s buildings, including churches, and improved its roads. Much of that elegance remains today.  The Companies continued to manage their estates until selling them under land laws enacted at the end of the century.

The Market Yard in Coleraine was constructed in 1829 to the same classical rules as buildings constructed 70 years earlier. The well proportioned elements of  the entrance were carefully laid out with the scale of the window recesses increased in size to harmonise with the central opening. It reflected a continuity in society with understood norms, hierarchies  and relationships.  

However, the preceding 50 years had been turbulent ones. The rational approach to architecture was a symptom of a general rational approach to thought, science, and religion. The Enlightenment, as it was termed, led to a questioning of old ways and the development of science. The American Revolution from 1765 was based upon similar ideas, as was the French Revolution of 1789. In 1798 the United Irishmen Rebellion erupted in this island with Presbyterians, (many of who had close links to America - 6 Scots Irish were included the 56 people who signed the Declaration of Independence)  very much to the fore in Ulster. The aim of the rebellion was full independence for the Irish Parliament, the establishment of a republic, (as in America and France),   and  equal rights for all men including Catholics. The main focus of the rebellion in Ulster was in counties Antrim and Down, and preparations in the Coleraine area appear to have been infiltrated before the rising, but there were incidents in nearby Toome, Maghera, Ballymena and Ballymoney. The response from the authorities was to crush the rebellion and then to instigate the Act of Union where the Irish and British Parliaments  voted to join the Kingdoms of Great Britain and  of Ireland into a single political entity; 'The United Kingdom of Great Britain and Ireland'. All had changed but the outward nature of society and its architecture remained the same.

In the eighteenth century the Georgian Style of architecture was also adopted by aspiring farmers, clerics and small business men. Some older buildings were adapted to the new approach. A good example of this in the Coleraine area is the Hasslet House in Castlerock were a seventeenth century building was 'Georgianised' by the insertion of a fanlight over the door and the insertion of large tripartite sash windows.