The first USS Argus, originally named USS Merrimack, was a brig in the United States Navy commissioned in 1803. She enforced the Embargo Act of 1807 and fought in the First Barbary War – taking part in the blockade of Tripoli and the capture of Derna – and the War of 1812. During the latter conflict, she had been audaciously raiding British merchant shipping in British home waters for a month, when the heavier British Cruizer-class brig-sloop HMS Pelican intercepted her. After a sharp fight during which Argus's captain, Master Commandant William Henry Allen, was mortally wounded, Argus surrendered when the crew of Pelican were about to board.

A brig is a type of sailing vessel defined by its rig: two masts which are both square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the latter part of the 19th century. In commercial use, they were gradually replaced by fore-and-aft rigged vessels such as schooners, as owners sought to reduce crew costs by having rigs that could be handled by fewer men. In Royal Navy use, brigs were retained for training use when the battle fleets consisted almost entirely of iron-hulled steamships.