18th and 19th centuries In the 17th, 18th, and early- to mid-19th centuries, and probably earlier still, horse-drawn Dublin-Cork traffic travelled via
Kilcullen,
Carlow,
Kilkenny,
Clonmel,
Ardfinnan,
Clogheen,
Ballyporeen, Kilworth, Fermoy and
Rathcormac. Much of the N8/
R639 route was built to connect the midlands to southern Tipperary and north County Cork as part of the Irish
turnpike road-building drive of the mid-18th century. However, some sections are much older, such as the segments between Cork and Fermoy,
Cashel and
Cahir and Durrow to Abbeyleix; the construction of these particular stretches cannot as yet be dated, though they were in place prior to 1714. The N8/R639 between Fermoy and Cahir via Mitchelstown was built sometime after 1811, while the R639/former N8 between Cashel and
Urlingford was built around 1739. At the same time, the route from Urlingford to Maryboro (modern-day Portlaoise) was substantially improved. In 1782 an unnamed English tourist in Ireland, known to historians as "X.Z.", gave a brief description of the route between Cashel and Urlingford: "From Cashel we rode fifteen miles of a bad road, through a bleak country to Urlingford, when we enter
Leinster province. The country now becomes more populous, better improved, and the roads much more agreeable for travelling."
20th and 21st centuries Some time after 1811 the gaps in the R639 between Fermoy and Cahir were filled, but the traditional route, known for much of the 20th century as the
T6, continued to run from Cahir to Dublin via Clonmel, Kilkenny and Carlow. The R639/N8 corridor did not become the official Dublin to Cork road until 1974 when it was designated as the N8, though several
Esso road atlases considered it to be the preferred route for motorists travelling between the two cities from at least the early 1960s. The N8 was improved at various times during the 1970s through to the early years of the 21st century. Improvement projects carried out on the road during the 1970s, 1980s and 1990s involved periodic widening, resurfacing and the replacement of
signposts. The first major improvement work carried out on the N8, post designation, involved the construction of a 4 km single carriageway bypass south-west of Cahir in County Tipperary. This opened to traffic in 1991, and remained the N8 until the M8 motorway was completed through South Tipperary on 25 July 2008. The 1991 N8 Cahir Bypass was then renumbered as part of the
N24, and was simultaneously designated as the
R639. (The original route of the N8 through Cahir town was redesignated a regional road in 1991, and was renumbered as part of the
R670). bypass, marks the entrance to Cork City. It was given motorway status and became a part of the M8 on 28 August 2009. The next major improvement entailed a realignment of the road so that it bypassed the village of
Glanmire for 6 km to the east. This
dual carriageway bypass, referred to in official documentation as the "Glanmire Bypass", cost £35 million and opened on 3 April 1992 after a construction period of almost seven years. In spring 2001, attention was turned to
Watergrasshill in County Cork. For many years regarded as a serious bottleneck on the N8, a wide median 7 km dual carriageway bypass was constructed and opened to traffic in September 2003 as the N8, with the former road through Watergrasshill becoming the R639. In 2004, the N8 through Cashel in County Tipperary was realigned with a narrow-median dual carriageway bypass to the east of that town. Again, the former N8 through Cashel was redesignated a regional road, and renumbered the R639. In July 2006, a circuitous and oft-criticized single carriageway relief road for Mitchelstown was opened to traffic around the west of the town. Ultimately, the N8 Cashel bypass was itself reclassified as part of the M8 motorway in July 2008. The changes took effect on 24 September 2008. Shortly prior to this, in October 2007, the section of N8 between Cashel and Cahir was bypassed by an early-opening segment of the now M8 motorway between junctions 9 and 10 and, for a 10-month period, this 13 km section of
high-quality dual carriageway was designated a section of the N8 (the former single carriageway became the R639). On 25 July 2008 the section of single carriageway N8 between Cahir and
Kilbehenny was also superseded by the new motorway, and this too was renumbered as the R639. This, in turn, was followed on 8 December 2008 by the length of road from Cashel to 2 km south of Cullahill in County Laois. In the meantime, the Watergrasshill to Fermoy section of the M8 had opened in October 2006. The Fermoy to Mitchelstown section of the M8 opened on 25 May 2009. The former single carriageway N8 that ran between these towns was then reclassified, for the most part, as the
R639 except for a section of the Mitchelstown Relief Road which became a part of the
N73 national secondary route.
Summary of major route improvements == See also ==