American Protective Association (APA), in U.S. history, an anti-Catholic, anti-immigrant group that briefly acquired a membership greater than 2,000,000 during the 1890s. A successor in spirit and outlook to the pre-Civil War Know-Nothing Party, the American Protective Association was founded by Henry F. Bowers at Clinton, Iowa, in 1887. It was a secret society that played upon the fears of rural Americans about the growth and political power of immigrant-populated cities.
Following William McKinley’s election as president in 1896 and the restoration of agricultural prosperity in the Midwest, membership dwindled. By 1900 the APA no longer exerted any noticeable political power, and it had disappeared entirely by 1911.