During a stay at the University of Chicago in the autumn of 1930, the Durkheimian sociologist Maurice Halbwachs wrote a series of eight short articles that were published in the Lyon daily newspaper Le Progrès under the title “Letters from the United States ”. For the first time, we are publishing this anonymous account (the letters were signed “M. H. ”), which has gone unnoticed until now, together with critical commentary. The letters are viewed against the backdrop of a whole series of “trips to America ” at the time and compared to Mr. Halbwachs’ correspondence with his family and his scholarly articles. It provides a close-up on what a sociologist did when travelling and the way he discussed the major topics that made the United States fascinating to his contemporaries: its material wealth, the absence of traditions and the assimilation problems facing immigrants and blacks.