The first printing press in the Americas (Mexico City, 1539)
Printing reached the western hemisphere in 1539, when the Seville printing house of Cromberger — under royal permission obtained in 1537 — established a press in Mexico City run by Juan Pablos, almost a century before the first press of English America. The earliest American imprints were bilingual doctrinal books in Spanish and Nahuatl.
Why this wins its question: The 1539 Mexican press precedes the Cambridge (Massachusetts) press of 1639 by a full century, yet histories of the book in America routinely start in New England. Claims here are bound to the scholarly digitization project that holds the earliest imprints themselves.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Juan Cromberger of Seville obtained royal permission in 1537 to establish a press in New Spain, and in June 1539 Juan Pablos signed the contract to run the House of Cromberger in Mexico City as compositor and administrator — the beginning of printing in the Americas.
Cromberger secured a monopoly on printing for New Spain; after his death in September 1540, Juan Pablos kept the press running and continued issuing imprints under the Cromberger name until at least 1544, consolidating a permanent printing trade in Mexico City.
The press's early production served the evangelization program — doctrinal texts in Spanish and in indigenous languages — which is why the earliest surviving American imprints are bilingual religious books rather than secular literature.