Long Spanish Surnames. Roman Catholic baptism, marriage Would love to hear your opinion on others “. Irish Americans are more Protestant than Catholic Let's finish off the week with a consultation for a mama who's due soon! 5,000 Most Common Last Names in the U.S. | Name Census Appendix:Spanish surnames (Latin America american catholic surnames. (In Portugal or Brazil that order is reversed). Trindade. Often, because occupational surnames exist in many languages, they simply turn from a common German name into a common English one. Looking Glass/Getty Images. Currently, the most popular last name in America is Smith, with a total count of 2,442,977 people who have the surname. Top 100 Irish surnames / last names and their meanings 1,932,812. This list of cool last name ideas will help you find a unique surname for your novel, fantasy, gaming or online characters. american catholic surnames