The Pacific Telegraph Company was one of the organizations responsible for constructing the telegraph line which resulted in the first transcontinental telegraph network in the United States. The company built the section of line between Julesburg, Colorado Territory (where it connected with existing telegraph networks to the eastern United States) and Salt Lake City, Utah Territory.
The Pacific Telegraph Company's line was completed on October 17, 1861 (although the first messages were not sent until October 18), allowing telegraphic messages from Salt Lake City to reach the eastern United States. The Overland Telegraph Company's line from California reached the telegraph office in downtown Salt Lake City on October 24, 1861, completing the transcontinental network. The Pacific Telegraph Company was absorbed into the Western Union Telegraph Company in 1864.