The purpose of this synthesis is to provide information that will assist those in both the transportation and preservation communities who make and execute decisions involving historic bridges. The synthesis includes a review of the general background of the "historic bridge issue," relevant legislation, bridge inventory procedures, significance criteria, constraints on bridge preservation, preservation alternatives, and bridge disposition criteria. Because the literature on this topic is scant, much of the information has been drawn from unpublished documents, interviews, and other "soft" sources. Some aspects of the topic have been the subject of review by others (both published and in process), and these have been drawn on liberally and with credit, where they exist.  This report is out of print and found at Order URL: https://onlinepubs.trb.org/onlinepubs/out_of_print.htm