Which trade union did Peter J. McGuire co-found in 1881, helping shape Labor Day history?

Peter J. McGuire co-founded the United Brotherhood of Carpenters and Joiners of America in 1881.

McGuire was a prominent American labor organizer who advocated for shorter working hours and stronger union organization. The carpenters’ union gave skilled building workers a national structure and became one of the major unions associated with the organized labor movement.

McGuire later helped establish the American Federation of Labor in 1886 and served as one of its leading figures. His connection with Labor Day comes from both his labor activism and the historical claim that he proposed a workers’ holiday, although Matthew Maguire is also credited with that proposal.

The United Brotherhood of Carpenters is not the same organization as the Knights of Labor or the AFL. The Knights were a broader labor organization founded earlier, while the AFL was a federation of separate unions rather than a single craft union.