It was originally known as the Edinburgh and Glasgow Union Canal, to celebrate the uniting of the two cities by the new canal network, but this name is rarely used today. The canal was designed by Hugh Baird, who oversaw the engineering work while it was being built between 1818 and 1822. Two of its construction workers were the famous murderers Burke and Hare.
The soliton, a form of wave, was first observed on the Union Canal in 1834, while its discoverer John Scott Russell was travelling along the canal in a horse-drawn boat. A modern aqueduct over the Edinburgh City Bypass is named after Russell.
Originally used for transporting coal, competition from the railways caused it to close to commercial use in the 1930s. The locks, connecting it to the Forth and Clyde Canal at Falkirk, were filled in and built over.
The canal is now used recreationally by canoeists at the Forth Canoe Club and rowers from schools and universities, e.g. the St Andrew Rowing Club. The Edinburgh Canal Society, the Bridge 19-40 Canal Society and Linlithgow Union Canal Society promote general use of the canal. They hire rowing boats and narrowboats, and they provide regular boat trips on the canal for the general public. Also of note are Re-Union Canal Boats who operate a social enterprise building and maintaining a boat for hire.
The Millennium Link, a project to restore both the Union and Forth and Clyde Canals, saw the two canals joined once again at the Falkirk end of the Union Canal, in the year 2000, by means of the Falkirk Wheel. The Falkirk Helix is a new six year project which will connect the Union Canal with the sea, by way of another unique boatlift in the shape of kelpies, the mythical water-horses.
The Union Canal is a contour canal, following a 73 metre (240ft) contour throughout its length. Originally, the only locks were those at Falkirk, to make the link to the Forth and Clyde canal. Now, there is one lock just before the Falkirk Wheel and a double lock just above. There is also a new tunnel where the canal passes under the Antonine Wall.
The canal has many aqueducts, including the Slateford Aqueduct that takes the canal over the Water of Leith in Edinburgh, the Almond Aqueduct near Ratho and the 810ft long Avon Aqueduct near Linlithgow, the second longest in the United Kingdom.
The Edinburgh end of the canal no longer reaches quite as far as it did (to 'Port Hopetoun' and 'Port Hamilton' basins which were filled in after the canal closed). Instead, the canal stops at Lochrin Basin at Fountainbridge.
Many of the stone bridges have keystones emblazoned with the coats of arms of Glasgow and Edinburgh, facing west and east respectively.
This area is currently being redeveloped for commercial and residential use, starting with Edinburgh Quay. British Waterways decided in June 2008 to market the area between Edinburgh Quay and Ashley Terrace Bridge as Edinburgh Canal Quarter.
With the canal now largely restored for both boating and for walkers and cyclists on the towpath, it is enjoying new life. Holiday barges are common in the spring and summer, while in area nearer the city centre there are even year-round residents living on narrowboats. A "floating restaurant" boat operates by arrangement, providing a meal whilst cruising.