[2] The springs are fed by underground flow through caverns in the limestone bedrock of the district from Lough Mask, a little over four miles (6.4 km) to the north.

[3] The river is only about one mile (1.6 km) long but some 100 yards (91 m) wide in places.

June to early July are particularly good, and salmon are taken in lesser numbers for the rest of the season.

The upper stretch has open access, while the lower part is managed by Ashford Castle, and local gillies are available.

The canal has become something of a tourist attraction in the village of Cong, County Mayo.