Typed copies of the official and private correspondence, 1814-1821, held in the McCord Museum in the William MacKay Papers. They consist mainly consist of military records such as commissions, 1813-1814, correspondence between members of the British Indian Department, including Lt. Col. Robert McDouall and his description of the siege of Prairie du Chien, with reference to the Omaeqnomenew (Menominee), Hocak (Winnebago), and Meskwaki (Fox) warriors who fought alongside British forces, as well as to the Potawatomi leader Main Poc (referred to as Marpock), 1814-1815 and copies of correspondence of Capt. Thomas Anderson with Lt Col. Robert McDouall on military actions, supplies and Indian relations, 1814-1815. There is also a newspaper clipping about Alexander MacKay and the partnership agreement admitting William MacKay and David Mackenzie into the North West Company in 1796.

This collection consists of translations from Terence, begun in 1778, and correspondence on military, political and private matters, 1787-1821, mostly addressed to Thomas Coutts, banker.

Consists of letter from Lord Selkirk to Captain Benjamin Walker dated 14 June 1816 concerning the sale of Selkirk’s land at Salmon River, New York, and his impending departure for the Red River.

Consisting of documents detailing the 1785 travels and observations of Joseph Hadfield through the Northwest fur trade of North America and to Niagara Falls (probably written after 1810). Observations are primarily economic in nature; however, there are also references to the geographical and cultural surroundings.

Consists of an English translation of a letter to the Marquis de la Jonquière written by Antoine-Louis Rouillé, comte de Jouy, secretary of state for the French Navy, at Versailles, dated 28 February 1750. The letter discusses an immediate release of prisoners of war taken during conflicts between the French and British colonies. It also includes a mention of Indigenous allies of England and France, and Indigenous people captured during the conflicts: "the Indian Prisoners among the two Nations be likewise released, but after all the French and English Prisoners are released" The letter also includes the name of examiner Josiah Willard, secretary of the province of Massachusetts-Bay.