The American Commission to Negotiate Peace following World War I was a research group created at the request of President Woodrow Wilson led by Col. Edward M. House. Established in autumn 1917, to investigate the geographical, economic, political, historic, and ethnological problems in Europe to prepare for peace negotiations. Information from the research group was to be used to inform the leaders in attendance at the peace conference. The Commission fell out of existence with the convening of the peace conference in January 1919. Jefferson turned down the request that he join the commission three times before he was finally persuaded by his friend and colleague Isaiah Bowman who told him that partaking in the negotiations would be a "national service." After some serious misgivings, Jefferson left his new wife Clara and his children first to New York City, where the first part of the commission took place and then to Hôtel de Crillon in Paris, France.
Jefferson faced many challenges he had never faced before such as not being able to choose his own cartographers, 12-16 hour workdays shut up in a single room, and having other delegation's demands thrust upon him. Jefferson also faced ideological issues of his own when leaders of "the Big Four" nations ignored the suggestions of the experts at the conference repeatedly. At 56 years old, the conference also wore on Jefferson's health. After five months in Paris, Jefferson requested to go home and it was granted; on June 1, 1919 Jefferson set sail for home leaving the peace conference behind.
The Mark S.W. Jefferson papers include materials pertaining to the American Commission to Negotiate Peace following World War I contain Jefferson's conference diary, a transcribed version of the diary by Geoffrey Martin, official delegation documents, maps, delegation territorial requests, correspondence between Jefferson and Allied delegations, and aerial photographs.