Overview
The First Congress implemented the Copyright clause of the U.S. Constitution in 1790. The Copyright Act of 1790, titled "An Act for the Encouragement of Learning, by Securing the Copies of Maps, Charts, and Books to the Authors and Proprietors of Such Copies," was modeled on the Statute of Anne.
The Act granted to American (but not foreign) authors the exclusive right to print, re-print, or publish their work for a period of fourteen years and to renew the rights for a second fourteen years. The law was intended to provide an incentive to authors to create original works by providing creators with a monopoly. At the same time, the monopoly was limited in order to stimulate creativity and the advancement of "science and the useful arts" through wide public access to works in the "public domain."
Source
Association of Research Libraries, “Copyright Timeline: A History of Copyright in the United States” (full-text).