Semington is a medium-sized village in West Wiltshire, England. It features 2 locks on the Kennet and Avon Canal, and is the start of the disused Wilts and Berks Canal. Its 2001 population was 830, and it is located 3 miles (5 km) from Melksham and 4 miles (7 km) from Trowbridge.
Semington civil parish includes the hamlets of Littlemarsh and Littleton.
Littlemarsh is located to the south of Semington, along the old course of A350 road. Littleton isn't populated anymore, and the only area currently designated as belonging to Littleton is the roundabout at the A350 and A361 road crossing.
The two Semington locks were built between 1718 and 1723 under the supervision of the engineer John Hore of Newbury and Quager of Hilperton and this stretch of the canal is now administered by British Waterways. They have a combined rise/fall of 16 ft 1 in (4.9 m). The two locks at Semington are known as Buckley's (numbered 15) and Barrett's (16).
Adjacent to the locks is the point at which the disused Wilts and Berks Canal joined the Kennet and Avon, and a group of determined enthusiasts are bent on restoring this canal to its former glory. East of the locks, the canal travels across the 2004 Semington Aqueduct, built to allow the A350 road to bypass Semington village. Another aqueduct carries the canal over Semington Brook.
The canal, towpath and adjacent hedges are good for wildlife and there have been recent sightings (August 2007) of watervoles (arvicola terrestris).
During the Second World War, Semington lay on GHQ Line which followed the path of the canal. Semington was designated as a centre of resistance: extensive anti-tank ditches were constructed to the east, south, and west of the village, these were overlooked by a number of pillboxes. The defences were constructed as a part of British anti-invasion preparations.
Semington has a pub, the Somerset Arms, which is popular with canal travellers, and a number of other small businesses. 1 km to the north of the village lies the ever-expanding Hampton Park West business park, which houses the large corporate headquarters of companies such as G-Plan, Avon Rubber plc and a large Wiltshire Police operations centre.