This barrow is close to the village of Chopwell, and there's also Chopwell Wood (the well chopped timber from which has been used in illustrious projects like Dunstanburgh Castle, the Tyne Bridge, and various warships. It's now managed by the Forestry Commission). Tony Henderson's article here explains that the name could come from 'Ceoppa Well' meaning a cattle watering place, or a local Saxon chief called Ceoppa.
He goes on to suggest that "legend has it he was buried in 685 at what is now Heavy Gate Farm, the site of a burial mound and well".
What a very specific date... sounds suspiciously like one of those Victorian Gentleman Speculations rather than local lore. But it makes a good story, and you get the well thrown into the local name for free.
The county SMR describes this as:
"A tree-covered round barrow of earth and stones, 22.45 m in diam, 2.21 m high with what appears to be a surrounding ditch 0.20 m deep and bank, 1.10 m max. width and 0.20 m high"
A quick look at some satellite images shows that it's not tree covered, and that the bank and ditch are just visible.