Strictly speaking, Portland Basin is the wide area on the main line of the canal.

The Ashton Canal was authorised by an Act of Parliament obtained in 1792, to connect the coal mining area around Oldham and the textile mills of Ashton-under-Lyne to Manchester.

The final 6.5 miles (10.5 km) were built as a tramway, as the quarries were too high to make access by canal economic, and the limestone was transhipped to barges at Bugsworth Basin.

[2] A campaign for the restoration of the Huddersfield Narrow Canal began in the same year, but was not completed until 2001, helped by public funding from the Millennium Commission.

The high breastshot waterwheel was constructed in 1841 to a suspension design introduced by Thomas Hewes and William Armstrong Fairburn and had rim gearing.

[8] Using a suspension system, akin to the spokes on a bicycle, allowed the wheel to be lighter than the wooden one it replaced.

[10] The Portland Basin hosts the Wooden Canal Boat Society which has restored and works six traditional narrowboats.

The Society was formed as a charitable company limited by guarantee in 1996, and took over the assets of the former Wooden Canal Boat Trust in 1997.

[11] The junction is located on the southern edge of Ashton-under-Lyne, and the Ashton Canal approaches it from the south-east.

[12] The Peak Forest Canal heads south, and is level for 7 miles (11 km) to the first of the sixteen Marple Locks.

[15] A slender bridge carries the towpath over the line to the aqueduct and the Peak Forest Canal.