The U.S. marine transportation system carries domestic and international freight. It also handles national and global transport of people. The needs of freight and passenger transportation are many and varied, and the capacity of the system to handle both has been constrained and congested due to increased need for freight and passenger capacity in different regions of our nation. Millions of Americans take cruises every year. Maritime vessels from the around the world call at U.S. ports delivering goods bound for the consumer market and material for industry. This chapter assesses the lock, port, terminal, vessel, and passenger capacity and performance of U.S. maritime transportation.