New London is a seaport city and a port of entry on the northeast coast of the United States, located at the mouth of the Thames River in New London County, Connecticut. It was one of the world's three busiest whaling ports for several decades beginning in the early 19th century, along with Nantucket and New Bedford, Massachusetts. The wealth that whaling brought into the city furnished the capital to fund much of the city's present architecture. The city subsequently became home to other shipping and manufacturing industries, but it has gradually lost most of its industrial heart.