The Union Bridge Company was a bridge fabricator and contractor with works in Buffalo, New York, and Athens, Pennsylvania. The Union Bridge company was formed in 1884 as a merger of several other bridge-building firms. Partners included George S. Field of Buffalo, Edmund B. Hayes of Buffalo, Charles MacDonald of New York City, Thomas C. Clarke of Seabright, NY and Charles Stewart Maurice of Athens, PA.

Edmund B. Hayes, also known as General Edmund Hayes, (1849–1923) was an engineer and businessman who built bridges and manufactured autos. He was a pioneer investor in the development of electrical power from Niagara Falls. His company installed the Steel Arch Bridge over the Niagara River and made the first power plant on the Canadian side of the river.