The term SAN JUAN, PUERTO RICO is a reference to the capital city of Puerto Rico. SAN Juan is the most populous city in Puerto Rico and is located on the northeastern coast of the island. It is known for its beautiful beaches, vibrant culture, and rich history. SAN Juan is also home to many important landmarks, including El Morro, a 16th century fort, and La Fortaleza, the oldest executive mansion in continuous use in the Americas.