The longest under ocean tunnel is the Seikan Tonneru. It is an underwater railway tunnel in Japan. It has a 14.5 mile long portion under the sea bed. The track level is 330 feet below the sea bed.
The Eisenhower Tunnel is the longest vehicular tunnel.
The Queensway tunnel under the River Mersey.
Hebesberger UT (Rossleithen) has the longest tunnel
The Kellerman Tunnel, exact details are ABOVE EYES ONLY>.
The world's longest canal tunnel is the Rove Tunnel in France. The Stad Ship Tunnel in Norway is shorter, wider, and deeper.
It's dug under the English Channel, which is described as an "arm of the Atlantic Ocean"
The world's longest canal that is also a tunnel is the Rove tunnel located in France. It was built in 1974. The longest tunnel in the world is a railroad tunnel that is 35 miles long through the Swiss Alps.
The 4.3 miles (7 kilometres) Severn Tunnel which runs between England and Wales was the longest railway tunnel in the UK. However the Severn Tunnel runs under the river Severn, so therefore is not purely under land only. The Channel tunnel is longer, but is an international tunnel and therefore not only in the UK. The longest tunnel in the UK that is purely under land was until recently the 6,230-yard/3.5-mile; 5.7-kilometre Totley tunnel between Grindleford and Dore stations on the Manchester-Sheffield line on the outskirts of Sheffield in Derbyshire. This has now been superseded by the 10.120km (6m 507y) twin bores of the London 2 (east) tunnel, part of the Channel Tunnel Rail Link between Stratford International and Ebbsfleet International.
Eurotunnel The Channel Tunnel
World's longest tunnel situated in New York state, United States named Delaware Aqueduct tunnel
Alas, no. There are several longer. The longest of all, the Paijanne water tunnel in Finland, is a water supply tunnel so probably doesn't count. The Seikan tunnel in Japan carries a narrow-gauge railway and is 33.5 miles long. The Channel tunnel is certainly the longest full-size railway tunnel at 31.3 miles. However, those crafty Swiss are currently at work under the Alps, and the Gotthard Base tunnel (also a standard gauge railway) will be 35.5 miles long, a clear winner.
The world's longest railroad tunnel is the Seikan Tunnel, it is 33.49 miles long.