Cumbernauld (/ˌkʌmbərˈnɔːld/; Scottish Gaelic: Comar nan Allt, lit. 'meeting of the streams') is a town in North Lanarkshire, Scotland. It lies within the historic county of Dunbartonshire. It is the tenth most-populous locality in Scotland and the most populated town in North Lanarkshire, positioned in the centre of Scotland's Central Belt. Geographically, Cumbernauld sits between east and west, being on the Scottish watershed between the Forth and the Clyde; however, it is culturally more weighted towards Glasgow and the New Town's planners aimed to fill 80% of its houses from Scotland's largest city to reduce housing pressure there.

For a period of time, Cumbernauld was chiefly populated around what is now called The Village with the medieval castle a short walk away surrounded by its own park grounds. The castle frequently hosted visiting royalty and the grounds were famous for their white cattle which were hunted in the oak forest. The town began to enlarge as the weaving industry of the village was supplemented by mining and quarrying as travel across Scotland became easier due to the Forth and Clyde Canal and the railways being constructed. Cumbernauld railway station, though some distance from the village, improved communications with Glasgow, Falkirk and Stirling.

Cumbernauld was designated as the site for a New Town on 9 December 1955. This led to rapid expansion and building for about 40 years until the town became established as the largest in North Lanarkshire. At the UK census in 2011, the population of Cumbernauld was approximately 52,000, housed in more than a dozen residential areas. Cumbernauld's economy is a mixture of some manufacturing, mainly on its industrial estates, as well as service industries in the town centre and in sites close to the M80. It was featured in Our World, the first live multinational multi-satellite television production.

Cumbernauld's name probably comes from the Gaelic comar nan allt, meaning "meeting of the burns or streams". There are differing views as to the etymology of this. One theory is that from its high point in the Central Belt, its streams flow both west to the River Clyde and east to the Firth of Forth so Cumbernauld's name is about it being on a watershed. Another theory ascribes the name to the meeting point of the Red Burn and Bog Stank streams within Cumbernauld Glen. 'Cumbernauld' is generally considered to be a Gaelic name. However, early forms containing Cumyr- hint at a Cumbric predecessor derived from *cömber, 'confluence' (cf. Welsh cymer, 'confluence'), synonymous with Aber. This seems to be suffixed with Cumbric *-ïn-alt, a topographical suffix perhaps referring to a hill or slope (Welsh yn allt, 'at a hill').

Cumbernauld's history stretches at least to Roman times, as Westerwood was a Roman fort on the Antonine Wall, the furthest and most northerly boundary of the Roman Empire. Two Roman temporary camps have been discovered and digitally reconstructed east of the fort, at Tollpark (now covered by Wardpark North) and at Garnhall, similar to the two at Dullatur. One of the most discussed Roman finds from Cumbernauld is a sandstone slab depicting Triton and a naked, kneeling captive. It was found on a farm at Arniebog (between the runway of Cumbernauld Airport and Westerwood Golf Course). The slab can now be viewed at the Hunterian Museum in Glasgow along with an uninscribed altar from Arniebog and other artefacts like the inscribed altar, and statuette found at Castlecary and an older copy of the Bridgeness Slab. In addition to these, an altarstone to Silvanus and the Sky dedicated by a centurion named Verecundus and his wife has been found. Cumbernauld also has the only Roman altar still in the open air in Scotland: the Carrick Stone. The stone has also been linked with Robert Bruce, being the place where he reportedly set up his standard on his way to Bannockburn. There is some evidence that coffins were laid on top of the stone on their way to the cemetery in Kirkintilloch and that the stone has been somewhat worn away.

There is a record of the charter of the lands of Lenzie and Cumbernauld, granted to William Comyn by Alexander II in 1216. Cumbernauld Castle was first built as a Norman-style motte and bailey castle. Owned by the Comyns, it was situated at the east end of the park, where the motte (mound) is still visible. The Flemings took possession of Cumbernauld Castle and its estate (c.1306) after Robert the Bruce murdered the Red Comyn. Robert Fleming was a staunch supporter of Bruce, and one of his companions that day. To provide proof that Comyn was dead, Fleming cut off his head in order to "let the deed shaw", a Fleming family motto ever since. On 1 October 1310 Robert the Bruce wrote to Edward II of England from Kildrum trying, unsuccessfully, to establish peace between Scotland and England. Abercromby describes Malcolm Fleming as returning home to Inverbervie with the formerly exiled 21-year-old King David II. Around 1371, the family built a second castle where the Cumbernauld House now stands. One castle wall exists but most of the stonework was recycled for the House or other buildings. King Robert III knighted Malcolm and granted Sir Malcolm Fleming and his heirs the charter to Cumbernauld Castle on 2 April 1406, just two days before the king's death. Malcolm (and his heir in 1427) were used as hostages to ransom James I back from the English. He also seems to have been arrested by James and imprisoned briefly in Dalkeith Castle. In 1440, this Malcolm Fleming attended the Black Dinner along with his 16-year-old friend Earl William Douglas and his 11-year-old brother David Douglas at Edinburgh Castle. Immediately after the dinner, at which a black bull's head was served, there was a trial on trumped-up charges and the brothers were beheaded in front of the 10-year-old King James II. Malcolm shared their fate three days later. Malcolm was succeeded by his son Robert.

The castle played host to the royalty of Scotland. James IV (1473–1513) wooed Margaret Drummond at Cumbernauld Castle, where Margaret's sister was married to Lord Fleming. The Drummond sisters lie buried in Dunblane Cathedral following their poisoning, possibly by a government determined to marry an unwilling King James to the sister of Henry VIII of England, Margaret Tudor. The murders made James IV a frequent visitor to Cumbernauld, Margaret Tudor accompanying him on one occasion. It is recorded that during this James' reign in 1500, the Black Death led to a special plea from the surviving people of Cumbernauld to the church authorities in Glasgow to allow them to establish their own cemetery rather than taking all their dead to St. Ninian's in Kirkintilloch. They were granted permission to do so, and used the ground at the existing Comyns' chapel which dates from the end of the 12th century.

James V is recorded as staying for a couple of days at the castle around 14 December 1529. In November 1542, Malcolm Fleming, Lord Chamberlain of Scotland to King James V, was taken prisoner by the English at the Battle of Solway Moss, but released at a ransom of 1,000 marks, paid on 1 July 1548. Mary, Queen of Scots visited the castle and reportedly planted a sweet chestnut tree in the grounds in 1561; she's also said to have planted a yew tree at Castlecary Castle, only a mile or two away, which still grows there. The whole great hall collapsed while the queen was staying at Commernalde on 26 January 1562, and 7 or 8 men were killed. Most of the queen's party were out hunting. Mary was not hurt and visited the relatives of those who were injured or killed in the village below. Royalty often visited the town to hunt the rare Scottish ox, or white cattle, which roamed in the woods around Cumbernauld. These woods were a surviving fragment of the ancient Caledonian Forest, in which the oxen abounded at least till 1571 and probably until the building of the new house. Many of these were deliberately killed by Regent Lennox's men and a plaintiff complains: "And amonges others greite enormyties perpetrated be th' erles men of werre they have slayne and destroyed the dere in John Fleming's forest of Cummernald and the quhit ky and bullis, to the gryt destructione of polecie and hinder of the commonweil. For that kynd of ky and bullis hes bein keipit this money yeiris in the said forest; and the like was not mentenit in ony uther partis of the Ile of Albion as is well knowen." "(In English, And amongst others, great enormities perpetrated by the Earl's soldiers, they have slain and destroyed the deer in John Fleming's forest of Cumbernauld and the white cows and bulls, to the great destruction of the park of the estate and hindering of the common good. For those kind of cows and bulls have been kept these many years in the said forest; and their like was not maintained in any other parts of the British Isles as is well known.")