It is named after Saint Seachnall, who established a church there in the 5th century.
Máel Sechnaill mac Domnaill was an ancestor from which the principal family of Brega, Ó Maoilsheachlainn, is descended. Dunshaughlin (or more specifically, the townland of Lagore) is famous for an ancient crannóg or settlement from the 7th century where a number of Irish antiquities were discovered.
Approximately 1.6 km south of the village is a preserved workhouse from An Gorta Mór which was abolished by the Irish State in the early twenties. The workhouse is currently under private ownership and is not open to the public.
Dunshaughlin is 29 km from Dublin on the R147, formally the N3 road but renamed after the M3 was opened. It is a growing satellite town of the Dublin. It has grown considerably over the last 20 years, the population in 1996 was 2,139, it was 3,063 by the census of 2002 and had risen to 3,384 by 2006.
Several housing estates centre on a main street with multiple retail units consisting of newsagents, pubs, take away food outlets, clothing stores and banks. There is also a business park on the outskirts of the town.
Dunshaughlin houses numerous public amenities, including a library, Meath County Council civic offices, a large community and sports centre, home to most of the town's organisations as well as a health centre. Equilibrium, a piece of public art by Orla de Bri is displayed at the county council offices. In 2006, a town park was opened by president Mary McAleese.
Dunshaughlin has two primary schools, St. Seachnall's National School and Gaelscoil na Ríthe. There is also a secondary school, Dunshaughlin Community College, run by Louth and Meath Education and Training Board, which was recently selected as one of 12 schools worldwide to take part in Microsoft's Innovative Schools programme.
Dunshaughlin has two primary schools- Gaelscoil na Ríthe and St. Seachnall's. It also has one secondary school- Dunshaughlin Community College ( DCC). DCC was established in 1933 and is part of the Louth and Meath Education and Training Board.  In 1985 a group of parents from the Dunshaughlin, Drumree and Culmullen areas set about providing All-Irish education for their young children. As a result, Gaelscoil na Ríthe was established. The school enjoyed sustained growth over the years with a new building provided in 1996. At present the school caters for a full stream of eight classes, over 200 pupils and has 12 teaching staff. St. Seachnall's was founded in 1835. It now has around 500 students (boys and girls) attending the school. In 2013 a new building was complete to cater for the growing number of students attending the school.
Dunshaughlin is served by Bus Éireann commuter services to Dublin, generally running at a frequency of every half-hour, with plans to increase frequency to every 15 minutes. Subject to the reopening of the Dublin–Navan railway line, there is a new station planned. Doubts have been raised, however, about the likelihood of the line being rebuilt. The old station was at Drumree, just outside Dunshaughlin.
The town is represented in sport by a Men's & Ladies Gaelic football team. The Men's team were Meath county champions 3 years in a row from 2000-2003. Their main sponsor is the local supermarket, SuperValu Dunshaughlin. The local soccer club is Dunshaughlin Youths  and is a very progressive club active both in the local community and in the North Dublin Schoolboys league . Other popular sports include tennis, golf and athletics. Dunshaughlin Athletic Club is traditionally considered a long-distance running club. However, the club has enjoyed the success of many juvenile sprinters of late, who have excelled at county, regional and national level. The towns golfing community takes great pride in its golf course "The Black Bush Golf Club". Around 3 km (1.9 mi) outside the village a new golfing resort designed by Jack Nicklaus has been created at Killeen Castle. The course hosted the 2011 Solheim Cup despite it not opening until 2008. The town also has a strong association with horse racing, in particular National Hunt racing. The leading flat race sprinter Sole Power, winner of the Nunthorpe Stakes and the King's Stand Stakes, is trained near the town by Edward Lynam. The Dunshaughlin and District Road Racing Supporters Club are a club of like minded motorcycle racing enthusiasts who provide and support a racing machine for the Irish road race championship.
The town has many skateboarders and has a skatepark, consisting of two skateboard ramps in the local park.
The Dunshaughlin workhouse was erected in 1840-41 on a 2 hectares (4.9 acres) site 2.5 km (1.6 mi) to the south of Dunshaughlin, the building was planned to accommodate 400 inmates. Its construction cost £4,938 plus £912 for fittings etc. The building was declared fit for habitaion on 12 May 1841, and received its first admissions on 17 May.
During the Irish Famine in the mid-1840s, many hundreds of people were crowded into the stone building in dreadful conditions. A burial ground was located to the rear of the workhouse, which you can still visit today, sometimes memorial services are conducted here for those who died during the famine.
In the post-famine years, the workhouse rarely had more than a few dozen inmates. During the First World War, the building was used to accommodate Belgian refugees, some of whom died there and were buried in the paupers' graveyard. In 1920-21, the building was taken over as a barracks by the Black and Tans during the Irish War of Independence.
Following the creation of the Irish Free State in 1922, the workhouse system was abolished. After many years of vacancy and semi dereliction the main building was taken into private ownership in the 1990s and now is primarily a private residence.
Dunshaughlin Harvest Festival is a fun-filled event for the whole family to enjoy. It is a three day festival, starting on September 23 and finishing up on the 25th. Now in its fifth year, this is an award-winning, annual festival with music, drama, dance, heritage events, food & craft markets, country sports and old-fashioned games for the children. As well as all the festivities, a harvest Queen is elected to be the face of the festival.
The Marvel Comic Character Shamrock was purportedly born in Dunshaughlin.