He was promoted to Lieutenant–Colonel at the end of 1808 and fought in the Battle of Corunna in Spain in early 1809 during the Peninsular War. In 1810, Ross was made a full Colonel as well as aide-de-camp to the King. In 1813, Ross was sent to serve under Arthur Wellesley and commanded his regiment at the battles of Vittoria, Roncesvalles, and Sorauren that year. He was seriously wounded in the left side of his neck at the Battle of Orthez, on 27 February 1814, and had just returned to service when he was given command of an expeditionary force to attack the United States.
War of 1812
Ross sailed to North America as a Major General to take charge of all British troops off the east coast of the United States. He personally led the British troops ashore in Benedict, Maryland, and marched through Upper Marlboro, Maryland, to the attack on the Americans at the Battle of Bladensburg on 24 August 1814, causing the hastily organised militia of the American army to collapse into a rout. Moving on from Bladensburg, Ross moved on to nearby Washington, D.C., and was fired upon; his horse was shot from under him. The public buildings, facilities and Navy Yards of the city, including the United States Capitol and the White House were burned as retaliation for destructive American raids into Canada, most notably the Americans' Burning of York earlier in 1813, which were themselves in retaliation to British raids into the United States. Controversy surrounds Ross's decision to destroy public property but spare a lot of private property during the burning. In reality several private properties were completely destroyed or damaged. , 1814 Ross then was persuaded to attack Baltimore, Maryland. His troops landed at the southern tip of the "Patapsco Neck" peninsula of southeastern Baltimore County at North Point, twelve miles southeast from the city, on the morning of 12 September 1814. En route to what would be the Battle of North Point, a part of the larger Battle of Baltimore, the British advance encountered American skirmishers. General Ross rode forward to personally direct his troops. An American sharpshooter shot him through the right arm into the chest. According to Baltimore tradition, two American riflemen, Daniel Wells, 18, and Henry McComas, 19, fired at him and one of them had fired the fatal shot. Ross died while he was being transported back to the fleet. Ross's body was preserved in a barrel of 129 gallons of Jamaican rum aboard HMS Tonnant. When the Tonnant was diverted to New Orleans for the forthcoming battle in January 1815, his body was shipped on the British ship HMS Royal Oak to Halifax, Nova Scotia, where his body was interred on 29 September 1814 in the Old Burying Ground.
He is commemorated by a 99-foot granite obelisk near the shoreline of Carlingford Lough in the Ross home village of Rostrevor, County Down in Northern Ireland, as well as by a monument in St Paul's Cathedral in London, England. The inscription on the monument reads: By the beginning of the Troubles in the 1960s, the monument in Rostrevor - now located in a predominantly Roman Catholic region - was largely neglected and overgrown by brambles; this may have contributed to its avoiding the same fate as Nelson's Pillar in Dublin, which was reportedly blown up by the IRA in 1966. After the Good Friday Agreement in 1998, the Newry and Mourne District Council, though largely Irish republican, agreed to refurbish the monument as part of Rostrevor's history, and it was reopened in 2008. Neither General Ross nor his immediate descendants were knighted or received a title of nobility. However, his descendants were given an augmentation of honour to the Ross armorial bearings and the family name was changed to the victory title"Ross-of-Bladensburg", which was granted to his widow. In honour of the history of Washington, D.C., there is also a portrait of Ross in the U. S. Capitol's rotunda and several illustrations in various War of 1812 historical sites in the Baltimore area, including a Monument near the site off Old North Point Road where he supposedly was shot. Additional details and exhibits have been preserved in various Baltimore historical institutions, such as the Star Spangled Banner Flag House and the National Park Service site of Fort McHenry's visitor center exhibits and in the local Dundalk-Patapsco Neck Historical Society museum in Dundalk, Maryland. Traditionally the two snipers/riflemen "Wells and McComas" were buried in a local churchyard mourned by their fellow soldiers and citizens of the Town, but later in the 1850s were exhumed and reburied after elaborate processions and funerals in a monumental tomb in Ashland Square, off of Orleans Street and North Gay Street in the Jonestown/Old Town neighborhood of East Baltimore. City streets were also named for them in South Baltimore.