Kirby Corporation operates domestic tank barges in the United States. Its Marine Transportation segment provides marine transportation service and towing vessel transporting bulk liquid product, as well as operates tank barge throughout the Mississippi River System, on the Gulf Intracoastal Waterway, coastwise along three United States coasts, and in Alaska and Hawaii. It also transport petrochemical, black oil, refined petroleum product, and agricultural chemicals by tank barge; and operates offshore dry-bulk barge and tugboat unit that are engaged in the offshore transportation of dry-bulk cargo in the United States coastal trade.