High Quality Content by WIKIPEDIA articles! The Outer Pennine Ring is an English canal ring which crosses the Pennines between Manchester, Leeds and Castleford. Its route follows parts of eight canals, and includes the longest canal tunnel in England. The ring was completed in 2001, with the opening of the Huddersfield Narrow Canal. Much of the route is shared with the North Pennine Ring, which crosses the Pennines by a different route on the southern leg.