Between 1830-1860, large numbers of German and Irish immigrants came to America due to overpopulation and famine in Europe. Germans made up the majority and settled in the Midwest, while Irish immigration increased dramatically in the 1840s due to the potato famine. Their arrival led to prejudice from nativist groups like the Know-Nothings, who feared Catholicism and wanted to restrict immigration. However, immigrants also contributed their cultures and traditions to America and provided cheap labor that benefited the economy.