Final answer:
The Know-Nothing Party was founded by Charles B. Allen and other nativists in the mid-19th century as a response to immigration.
Step-by-step explanation:
The Know-Nothing Party, also known as the American Party, was founded by a group of nativists and anti-immigrant activists in the mid-19th century. One of the influential figures in the formation of the party was Charles B. Allen, a lawyer and politician from New York. The party gained traction in the late 1840s and early 1850s, particularly in response to the influx of Irish and German immigrants.
Learn more about Founding of the Know-Nothing Party