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Allt-yr-yn Lock and Little Lock, with intermediate bridge and basin, Monmouthshire and Brecon Canal

A Grade II Listed Building in Allt-yr-Yn, Newport

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Latitude: 51.5947 / 51°35'40"N

Longitude: -3.017 / 3°1'1"W

OS Eastings: 329650

OS Northings: 188915

OS Grid: ST296889

Mapcode National: GBR J4.BRV6

Mapcode Global: VH7BC.N5DV

Entry Name: Allt-yr-yn Lock and Little Lock, with intermediate bridge and basin, Monmouthshire and Brecon Canal

Listing Date: 14 September 1999

Last Amended: 14 September 1999

Grade: II

Source: Cadw

Source ID: 22328

Building Class: Transport

Location: Situated approximately 30 metres SE of Grove Farm. Bridge carries track to Allt-yr-yn. Allt-yr-yn Lock immediately W. Stone lined basin E of bridge with Little Lock immediately E.

County: Newport

Community: Allt-yr-yn (Allt-yr-ynn)

Community: Allt-yr-Yn

Locality: Allt-yr-yn

Built-Up Area: Newport

Traditional County: Monmouthshire

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The eastern branch of the Monmouthshire and Brecon Canal was authorised by Act of Parliament in 1792, and officially opened in 1799. It ran from Newport to Pontnewynydd, and was engineered by Thomas Dadford Jnr. The canal connected with several tramroads belonging to the same company (Monmouthshire Canal Navigational Company), carrying coal down to the wharves. The branch was 17.7 km long, and rose 136.2 metres through 42 locks. The contemporary western branch, 19 km long, ran to Crumlin. In 1812, the eastern branch was connected to the Brecon and Abergavenny Canal at Pontymoile Basin, and this became the main line. In 1853-55, the Monmouthshire Railway and Canal Company built a railway down to Newport, the company amalgamating with the Great Western Railway in 1880. The canal then became increasingly disused. The Crumlin branch closed in 1949, the main line in 1962.


Allt-yr-yn lock chamber of both rubble and brick construction; tooled sandstone copings. Rebate for removed lock gate to E. Rubble weir at W end, with splayed retaining walls beyond. Narrow bridge immediately E with segmental arch; roughly dressed stone voussoirs. Splayed parapets with tooled chamfered copings, partly replaced in cement. Stone-lined basin E of bridge approximately 12 metres long. Little Lock chamber has rubble-built weir to W end and rebates for removed lock gates to E end. Chamber walls of rubble and brick construction. Squared sandstone copings. Straight retaining cheek-walls to E of Little Lock.

Reasons for Listing

Listed as a significant element of the engineering works associated with the Monmouthshire and Brecon Canal.

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