And there’s also Wat’s Dyke, which is centuries older than Offa’s Dyke, and may have inspired it.
Ah yes. Wodenes Dyke.
"In its most perfect state it began at Andover, in Hampshire, ran through the counties of Berkshire, Wiltshire, and Somersetshire, and terminated in the “Severn Sea” or Bristol Channel. It was called Wodenes Dyke by the Saxons, contracted into Wondes-dyke, and corrupted to Wans-dyke, as Wodenes-daeg is into Wednes-day."