Coraopolis ( /kɔərɪɒplɨs/) is a borough in Allegheny County, Pennsylvania, USA. The population was 5,677 at the 2010 census. In 1940 the population peaked at 11,086. It is a small community located to the west of Pittsburgh, along the Ohio River and to the east of the Pittsburgh International Airport. The borough is noted for its steep topography, numerous brick streets and many large, old and exquisite homes. The American Bridge Company is headquartered in Coraopolis.
Coraopolis has a history replete with the names found on the borough's street signs; names like Montour, Vance, Ferree, McCabe, Neely and Watson.
On April 3, 1769, Andrew Montour, an Indian interpreter who had provided service to English settlers during the French and Indian War, was granted a land patent for approximately 350 acres (1.4 km2) of what would later become the borough of Coraopolis and Neville Island. It is a matter of uncertainty whether he ever lived upon this tract, and highly probable that his residence was not long. The first permanent white settler in Coraopolis was Capt. Robert Vance, who settled in the vicinity of Montour's tract around 1773, just prior to the beginning of the American Revolution. Vance, a Virginian, had been a member of the regiment commanded by George Washington at the Braddock expedition during the French and Indian War. For the protection of himself and his neighbors, of whom several arrived within a few years, Vance had a log stockade built with a stone blockhouse to protect the area against Indian raids. This was known as Vance Fort (or Fort Vance). The site of the fort was around present-day Broadway and Chestnut streets, near Second Avenue. Over time the community grew and developed, and it became known as Middletown in the 1800s, because it was situated midway between Pittsburgh and Beaver, Pennsylvania.