The Act Prohibiting Importation of Slaves of 1807 (2 Stat. 426, enacted March 2, 1807) is a United States federal law that provided that no new slaves were permitted to be imported into the United States. It took effect on January 1, 1808, the earliest date permitted by the United States Constitution. The domestic slave trade within the U.S. was not affected by the 1807 law. Indeed, with the legal supply of imported slaves terminated, the domestic trade increased in importance. In addition, some smuggling of slaves persisted.