On 10 May 1809, Portugal, Oporto. 2/66th. Landed at Ovar on 10 May. On 12 May the whole force was at Oporto on left bank of Douro. The 2/66th with the Buffs and 48th, occupied the Seminary and held it against all attacks. On 15 May it reached Braga and rested, then retraced its steps to Oporto
On 28 June 1809, Portugal. 2/66th moved towards the Spanish frontier, arriving at Castelo Branco on 30 June. On 3 July it crossed the frontier into Spain, advanced to Coria on 4 July and reached Plasencia on 8 July.
During July 1809, Ceylon, Trincomalee. 1/66th. 400 men embarked at short notice for Madras. In August the Regiment started to march to Hyderabad, but halted at Gooty. From here they were returned to Trincomalee. In September a detachment of 300 sent to Madras, but owing to a misunderstanding they were returned to Trincomalee
On 18 July 1809, Spain. 2/66th again advanced, this time south east. On 22 July it crossed the watershed between the Tietar and Targus. On 20 August Wellington moved to cantonments in the Guadiana valley at Merida. The 66th lost 100 men here because of fever. During September the Regiment arrived at Montijo.
During November Wellington decided to withdraw his forces to Portugal.
On 8 Dec 1809, Spain, Abrantes. 2/66th started their withdrawal finishing at Abrantes. In February 1810 it was sent to Portalegre on the Spanish frontier and on 9 June it received orders to cross the Tagus
During 1810, Sicily. 1/62nd. Operation on coast opposite Calabria against the French forces under Murat who had assembled a large force for the purpose of invading the island. However, his attempts were foiled, and he was prevented from landing to the south of Messina by the enemy's batteries. In this attempt he lost 1500 men
On 2 Oct 1810, Portugal, Alhandra. After the 2/66th took a small part in the Battle of Busaco on 27 September, the Regiment retreated to Alhandra on the right bank of the Tagus.
On 12 October the 2/66th moved north to join Wellington's forces.
During 1811, Sicily. 1/62nd. Three companies of the Regiment embarked on board the 'Imperiuse' and 'Thames' frigates. Landing at Palinure on the Neapolitan coast. Maintaining their ground for three days against a thousand strong enemy. Succeeding in destroying enemy batteries and bringing off a valuable convoy. Lieutenant Kay of the Light Company was killed and Captain Oldham, Grenadiers, severely wounded, together with three Other Ranks
On 15 May 1811, Spain, Albuera. 2/66th and rest of Colbourne's Brigade rejoined the 2nd Division here. Due to bad planning the 66th were attacked both from the front and the rear. Their losses were frightful and they practically ceased to exist.
During July 1811, Spain. 2/66th. Major Nichol took command of the 66th wing of this Battalion.
After heavy losses at Albuera it was found necessary to form a Provisional Battalion from seven infantry regiments. All except the 2/31st and the 2/66th who soon resumed their separate constitution. These two remained as the First Provisional Battalion until 1814
On 1 July 1812, Canada. War was declared by the United States on 23 June
400 armed men collected to resist them being drafted into the Militia. The 49th Light Company sent to disperse them. The Light Company was deployed back to Montreal on 3 July
On 1 Aug 1812, Canada, Kingston. One company of the 49th deployed here after escorting stores. Three more companies deployed to join them on 2 August and the rest of the Regiment deployed there on 13 August
On 22 Aug 1812, Canada, Kingston. Whole Regiment ordered across Lake Ontario to Fort George on the Canadian (western) side of Niagara River.
On 18 September six companies deployed at Fort George and four companies re-deployed to Kingston.
On 20 September the Grenadier Company was ordered to march to Queenstown, approximately seven miles up river and seven miles below the falls
On 9 Oct 1812, Canada. 49th involved when the US Navy attacked the two brigs, 'Caledonia' and 'Detroit', at Fort Erie.
On 11 October Captain Dennis said that his detachment of the 49th at Queenstown was in a mutinous condition.
For two days from 12 October the Americans attacked Queenstown. The Light Company under Captain Williams, and the Grenadier Company under Captain Dennis of 49th involved in a battle which led to a British victory against superior numbers. After the battle a local armistice was granted to the Americans so they could bury their dead. This was afterwards extended until one side should give thirty hours notice of termination