Grand Union Canal
England's longest canal network — 137 miles of towpath, narrowboats and waterside heritage from London to Birmingham
England's longest canal network — 137 miles of towpath, narrowboats and waterside heritage from London to Birmingham
The Grand Union Canal stretches 137 miles from the heart of London to central Birmingham, making it the longest canal in England. Formed in 1929 through the merger of several older waterways — most notably the Grand Junction Canal of 1793 — it passes through some of the finest scenery in the Home Counties, from the mansion-lined pool at Little Venice to the beech woods of the Chiltern Hills.
For visitors based in London, the canal offers an easy escape into countryside that feels far removed from the city. The towpath is free to walk or cycle along its entire length, and narrowboat trips run from several points including Little Venice and Rickmansworth. Canalside pubs, working locks and abundant wildlife make this one of the most rewarding waterside walks within reach of the capital.
The canal that runs through London today began life as the Grand Junction Canal, authorised by an Act of Parliament in 1793 and fully opened in 1805. Its purpose was direct and commercial — to create a shorter route between London and Birmingham, cutting 60 miles off the existing path via the Oxford Canal and the River Thames. The engineer William Jessop oversaw the main line, which ran from Braunston in Northamptonshire down through the Chiltern Hills to a terminus at Paddington, then a village on the western edge of London.
By the early twentieth century, competition from railways had diminished canal trade, and in 1929 the Grand Junction merged with the Warwick and Napton Canal, the Birmingham and Warwick Junction Canal and five smaller waterways to form the Grand Union Canal. A government-funded modernisation programme in the 1930s widened many of the narrow locks between Braunston and Birmingham to take wider boats, though the locks south of Braunston remained narrow. The Duke of Kent opened the new broad locks at Hatton in 1934, and further improvements continued until 1937. Commercial carrying dwindled through the mid-twentieth century, and the last regular cargo runs ended in the 1970s.
The most accessible stretch for visitors begins at Little Venice in Maida Vale, where the Grand Union meets the Regent's Canal at a wide, tree-lined pool known as Browning's Pool. From here, you can walk east along the Regent's Canal towpath to Camden Lock in about 45 minutes, passing through the Maida Hill Tunnel, skirting the northern boundary of Regent's Park and passing the back of London Zoo before emerging at Camden's famous market.
Heading west and then north from Little Venice, the Grand Union towpath follows the Paddington Arm through residential streets before opening out into the suburbs. The canal passes through Alperton, Greenford and Southall — areas with a strong South Asian community, where canalside temples and restaurants add unexpected colour to the walk. Beyond the M25, the character changes entirely. The canal enters the Colne Valley at Rickmansworth, where the River Colne, the Chess and several lakes create a network of waterways and wetlands. Cassiobury Park in Watford is a highlight, with four locks carrying the canal through mature woodland that the Shell Guide to Inland Waterways singled out as among the finest urban canal scenery in Britain.
North of Watford, the canal climbs through Kings Langley and Hemel Hempstead towards the Chiltern summit at Tring. The landscape becomes increasingly rural, with the towpath running through beech woodland, past chalk grassland and alongside the four Tring Reservoirs, built between 1802 and 1839 to feed the summit level. These reservoirs are now a National Nature Reserve, managed by Natural England, and attract birdwatchers year-round — great crested grebes, grey herons and overwintering teal and shoveler are regular sights.
The market town of Berkhamsted sits directly on the canal, with the ruins of its Norman castle visible from the towpath. Further north, the canal descends through Marsworth and Leighton Buzzard before continuing across the Midlands to Birmingham. While most London visitors will explore the southern sections, the full towpath is a designated long-distance walking route of 147 miles, waymarked by the Canal and River Trust and walkable in stages over several days.
The towpath is entirely free to walk or cycle. Narrowboat trip prices vary by operator and route. The London Waterbus Company runs regular scheduled services between Little Venice and Camden Lock. Day boat hire is available from several marinas along the canal, typically starting from around £150 for a half day.
Warwick Avenue tube station is a five minute walk from the canal basin and gives immediate access to the towpath in both directions. Head east for Camden Lock or north to follow the Grand Union into the suburbs.
The narrowboat trip from Little Venice to Camden Lock takes about 45 minutes and passes through Regent's Park and London Zoo. It is a relaxing way to see a stretch of the canal without walking the full towpath.
The towpath is well surfaced for cycling in most sections, particularly between Little Venice and Uxbridge. Give way to pedestrians and slow down near locks and narrow bridges. Some sections can be muddy after rain.
Watford Junction is 20 minutes from London Euston. Walk to Cassiobury Park and pick up the towpath heading north through the locks and into the Colne Valley towards Rickmansworth for a rewarding half-day outing.
The four reservoirs near Tring are a National Nature Reserve with excellent birdwatching. Great crested grebes breed here in summer and wildfowl overwinter in large numbers. The towpath runs right alongside them.
London Travel Writer · 12+ years covering UK attractions and tourism
Last reviewed: March 10, 2026
