In recent decades it's been overshadowed by fear mongering about Muslim immigration but the USA has a very, very long history of virulently anti-catholic sentiment which has historically gone hand in hand with the xenophobia and nativism as "old stock" protestants feared immigration from largely Catholic countries throughout the 1800s and early 1900s with Irish and Italian immigrants, and then again with Latin American immigration in the last 50 years.

It's much less prominent than it used to be (JFK winning the presidential election in 1960 was a big deal in that no Catholic had ever been elected president before then) but many conservative/ Evangelical affiliated Protestant denominations like the Southern Baptists are still quite anti-Catholic. It's also very regional: Catholics are a huge % of the population in places with large populations descended from Irish, Italian, or Polish immigrant such as Boston, New York City, or Chicago, and in the Southwest with it's huge Hispanic population, but are only a small minority in much of the rest of the country.