In maritime law . Commerce and navigation between different places along the coast of the United States , as distinguished from commerce with ports in foreign countries. Commercial intercourse carried on between different districts in different states, different districts in the same state, or different places in the same district, on the sea-coast or on a navigable river. Steamboat Co. v. Livingston, 3 Cow. (N. Y.) 747; San Francisco v. California Steam Xav. Co.. 10 Cal. 507; U. S. v. Pope, 28 Fed. Cas. 630; Ravesies v. U. S. (D. C.) 35 Fed. 919