INTRODUCTION This is No. 3 of a miscellaneous series of reports prepared jointly by the Board of Engineers for Rivers and Harbors, War Department, and the Bureau of Operations, United States Shipping Board. The juestion of the establishment in the United States of foreign trade zones (in Europe known as free ports) has been under consideration by Congress at various times during recent years, but no action thereon has as yet been taken. The subject relates to the functions of the Corps of Engineers, War Department, and the United States Shipping Board, and also falls directly within the scope of authority granted in section,8 of the merchant marine act for joint investigation by these establishments. It is generally recognized that while the immediate convenience claimed for free ports or foreign trade zones is the elimination of customs restrictions, the main argument in their favor relates to the development of transshipment and consignment trade and to the strengthening of the merchant marine. Closely related to the problems of the merchant marine is the question of adequate port development in the United States and the provision of channels properly located and of sufficient depth and width to meet the needs of the classes of vessels which the ports are likely to attract. In order to have complete and current data with respect to the free ports of Europe, the cooperation of the State Department was sought with a view to obtaining from consular officers abroad reports covering questions upon which the available information was obsolete or inadequate. These reports, with other data of interest to the study, are printed in part 2 of this volume. The War Department and the Shipping Board desire to express their appreciation of the efficient cooperation of the State Department in making available much information of value for the consideration of the subject. Analysis of this and other information already available is contained in part 1 of this report.