Hadrian's Wall did not stop at the sea. West of Bowness, the Romans continued their frontier along the Cumbrian coast with a chain of milefortlets and watchtowers, guarding against raiders who might sail across the Solway Firth. Bank Mill tower 15a is one of those coastal towers, set on the low ground near Silloth, and its remains are slight, though the logic is clear: from here, a sentry could see the whole estuary, and a signal could pass quickly along the line. The coast defences belong to the same UNESCO frontier listing as the wall itself.
The landscape is the Solway Plain, a flat, windy country of big skies, salt marsh and sheep pasture, with the hills of southern Scotland across the water. Silloth, a Victorian seaside town of nearly three thousand people, has a wide green on the front, a harbour and a fine fish and chip shop. Maryport, farther down the coast, was once a Roman fort, Alauna, and the Senhouse Roman Museum, set on a headland, houses a remarkable collection of altar stones. Fuel is available in Silloth and Maryport, and Aspatria and Dearham are smaller.
The coast road, the B5300, is a delight for riders. It runs close to the sea, through Allonby and Mawbray, with long, gentle bends, big views and not much traffic, and the surface is usually decent. When the wind blows off the Irish Sea, it can be strong enough to push a bike sideways, so grip tight on the open stretches. Sunsets over the Solway, with the hills of Galloway turning purple, are among the best in England.
Spring brings lambs and gorse, summer brings holidaymakers to the beaches, and autumn brings geese. Thousands of barnacle geese and pink-footed geese arrive from the Arctic to feed on the marshes, filling the air with their noise at dawn and dusk. Winter storms can throw spray across the road, so check the tide times before you ride the low sections. A cup of tea and a bacon sandwich at a seafront café make a fine stop.