How Beaver County Was Named
The name "Beaver" was given to the county from the stream and town called at the time of its earliest settlers, and the town had been named for the stream. As to the origin of the name of the stream itself, we need not be in any doubt. It was a translation into English of the Indian word for beaver, the much-prized animal after which the local Indians had named the stream. The Delawares called the stream Amockwi-sipu, or literally, "beaver stream." They gave this name to the creek because of its being a favorite home of
The French, who were the first whites to reach this region, merely translated the Indian name for the stream calling it, as we have learned from a map in Pouchot's memoirs, River au Castor, (Beaver River), and the English when they arrived, called it the same name.
Before the mapping of the town and outlets at the mouth of the stream, under the Act of September 28, 1791, the point was known by the Indian names of Sawkunk and Shingoe's Town, later by the English as "the old French town." Later it was called McIntosh, from the fort there and the town that was created by legislative action was called Beaver. And it was determined to be county seat of the new county in its beginning stage of development.
Thus, it was natural that when the time came for the creation of the county, it should receive a name associated with the most important stream and locality belonging distinctively to it's territory, and was accordingly called Beaver.
History of Beaver County, Volume 1, 1904