La Fortaleza is the Governor's mansion. It's located in Old San Juan at the western section at the end of Fortaleza Street and faces the bay.
The Fortaleza is the home of several governors since the Spanish and American colonial rule. It's a beautiful mansion which was originally built as a fortress in 1540 and has gone through several restorations throughout this long history.
There are several free tours in English and Spanish and proper attire is a must.
Please Note: This is a World Heritage Site.
La Fortaleza was built between 1533 and 1540 as the Spanish settlement's very first fortification, making it a few years older than El Morro. In fact, when you go on a tour of the residence, you can see that the back of the building still looks very much like a fort. However, La Fortaleza is mostly known for being the official residence of the Governor of Puerto Rico since the mid-16th century, making it the oldest Governor's Mansion still in use in the Western Hemisphere. In its nearly five centuries of existence it has been remodelled extensively. Among other things, in the mid-19th century, the front of the building was completely changed in order to make the Governor's Mansion look less like a fortress and more like a palace.
To go on a tour of La Fortaleza, the best thing to do is to stop by the tour office (the big yellow building on Calle Fortaleza) early in the day. Schedules change daily, so they will let you know when the next English or Spanish tours are available. Admission is $3, and to be allowed to go on the tour you must be properly dressed (nothing above the knee, no sleeveless shirts). We ended up going on the Spanish gardens tour as this was the one that fit our schedule the best and our guide made sure to translate the most important pieces of information. She explained the history of the house, we were able to visit the tower where Santa Catalina's chapel is located (and from where La Fortaleza derives its nickname of "Palacio de Santa Catalina"), and we then walked through the Mansion's beautiful gardens. It was a very interesting tour!
A short little walk brings you out the San Juan Gate to La Fortaleza. This area is kept up very nicely with flowers and a dock out over the water. This is now the official residence of the Governor of Puerto Rico. It was built between 1533 and 1550 to defend the harbor of San Juan. This is the oldest executive mansion in continuous use in the Americas and is on the UNESCO World Heritage List.