In June 1814, de Watteville was transferred briefly to the Richelieu River sector, but on 8 August, he was appointed to command the ""Right Division"" on the Niagara River in Upper Canada (succeeding Major General Phineas Riall, who had been wounded and taken prisoner by the Americans at the Battle of Lundy's Lane). He reported to the siege lines around Fort Erie on 15 August. On 17 September, the Americans made a sortie against de Watteville's lines, leading to a bloody engagement in which about 600 men were killed or wounded on each side.