The area of Big Beaver Township suffered growth and loss over the next seventy five years. Two world wars and several depressions saw the population and industry decline. The Borough of Wampum, in search of a larger tax base, decided to annex the Medusa Cement Plant from Big Beaver Township. At that time, according to Pennsylvania state law, a township could not prevent a borough from annexing property and Wampum succeeded in annexing the property into Wampum. Shortly after this, the Borough of Ellwood began to consider annexing the property south of the cement plant. In 1958, the township trustees began the process of changing Big Beaver Township into the Borough of New Beaver in order to prevent the further annexation. The charter was signed on November 18, 1959, however the community continued to operate as a township until elections could be held in 1961.