The archive contains personal and professional papers of Lord McNair throughout his life. It also contains papers of other members of his family, which had been stored in the same chests and boxes, and reference material about Lord McNair after his death. There is substantial correspondence belonging to family members, particularly his wife.

Lord McNair's correspondence includes a fair amount of a professional nature from fellow lawyers, some politicians and long-standing friends - these include Lord Macmillan, Lord Wright, Lord Nathan of Churt, Lord Beveridge, Harold Laski, the Earl of Derby, Lord Sankey, President Max Huber and Dag Hammarskjold.

There are also lectures and speeches and reference material covering the whole period of Lord McNair's public career.