Colonial Office 537 is one of the "artificial" classes of the Colonial Office records created by the Public Record Office after the papers had passed from current use. Therefore, it is composed of miscellaneous records not properly appropriate to any other Colonial Office class, or records which were retained by the Colonial Office for a longer period than the remainder of the class to which they belonged. Miscellaneous material includes records relating to the Civil Service Commission, the Civil Service Uniform, Secret Service pensions, and naval cadetships.
The National Archives of Canada has acquired microfilm copies of volumes 22 to 1172 of CO 537 relating to Canada, New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland, British Columbia and the North West including Red River. This material is available on microfilm reels B-812 to B-830, B-3233 to B-3240 and B-3521 to B-3524. It includes correspondence, minutes, memoranda, telegrams and other communications from public and private individuals. Most of the documents are classified as "secret", "private", or "confidential". However, these designations had different meanings at different times.
The class is rich in information relating to colonial defence, including memoranda on the distribution of troops, state of garrisons, the Admiralty establishment on the Great Lakes, naval defence of North America, militia training facilities, military matters connected with Louis Riel and the Red River and North West disturbances, and Canadian raftsmen for the Nile expedition. There is a substantial amount of material concerning Fenian activities, information on their strength and plans for defence. Other subjects include secret service pensions, acquisition of Rupert's Land from the Hudson's Bay Company, fishery disputes in Newfoundland, the boundary between Canada and the United States, the Canadian Pacific Railway, the Treaty of Washington, the political situation in British Columbia, a plot to abduct Princess Louise, Behring Sea negotiations, reciprocity discussions in 1891, confederation and Newfoundland 1869-1895, plots against Lord Lansdowne and Joseph Chamberlain, federation of the Maritime colonies, state of repairs of governors' residences in North America and so on.