There's a plaque in the floor near the altar where he used to be buried, before Charles II's men dug it up, hanged it, beheaded it, and if I'm not mistaken, burned the body. There's no body left to find.
I've got an ancestor that was dispatched in a like manner for the regicide of Charles I.
They didn't burn it. They supposedly interred the dismembered torso under Tyburn gallows, along with the remains of his fellow "conspirators." But there remains some doubt, at least in some peoples' minds, as to whether the body of Cromwell was even among those disinterred after the Restoration.