The USS Pargo (SS-4) was a United States Navy submarine, launched on March 28, 1903. It was the fourth submarine in the U.S. Navy and was designed for coastal defense. The Pargo was a part of the early development of submarine technology, featuring a single hull and a surface displacement of about 200 tons. The submarine was powered by a combination of electric batteries and a gasoline engine. It had a length of 130 feet and could reach speeds of 8 knots on the surface. The Pargo served primarily in training roles and was decommissioned in 1910, marking an important step in the evolution of naval warfare.