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Lock No 66

A Grade II Listed Building in Llangynidr, Powys

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Latitude: 51.8706 / 51°52'14"N

Longitude: -3.25 / 3°15'0"W

OS Eastings: 314032

OS Northings: 219849

OS Grid: SO140198

Mapcode National: GBR YW.S6H1

Mapcode Global: VH6CF.M76V

Entry Name: Lock No 66

Listing Date: 28 August 1998

Last Amended: 28 August 1998

Grade: II

Source: Cadw

Source ID: 20389

Building Class: Transport

Location: To the west of Cwm Crawnon; the lower of a group of three locks.

County: Powys

Community: Llangynidr

Community: Llangynidr

Locality: Cwm Crawnon

Built-Up Area: Llangynidr

Traditional County: Brecknockshire

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The Brecknock and Abergavenny Canal was promoted in 1792 to connect the upper Usk valley with the Monmouthshire Canal at Pontymoile and from there to the sea at Newport. The first section, between Gilwern and Talybont and including Llangynidr, was cut between 1797 and 1799, with the upper section between Talybont and Brecon opened in 1800, both sections engineered by Thomas Dadford. The lower section between Gilwern and Pontymoile was completed in 1812 and was engineered by William Crosley. In 1865 the Brecknock and Abergavenny and the Monmouthshire Canals merged to become the Monmouthshire and Brecon Canal, which was later incorporated into the Great Western Railway. The canal was an important artery for trade in iron from the works in the north-east corner of the coalfield and for lime and coal to supply the Usk Valley. The last toll was taken on the canal at Llangynidr in 1933. Restoration of the canal began in 1964.


This is the lower of a group of three locks that completes the flight of five west of Llangynidr, ending a 37km pound and raising the canal 17m towards Brecon. As with the neighbouring locks the chamber has been partly refaced in brick and the gates have been replaced in 1993. By-pass overflow to west.

Reasons for Listing

Included for its special interest as one of a flight of locks that form part of a group of structures on this stretch of the Brecknock and Abergavenny Canal which was completed in 1799.

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