This home was built circa 1747, but it's a bit unclear as to how it got its name. Most likely it's because the owner Joseph Gorgas apparently allowed members of the Baptists in Ephrata to stay with him. Today, the stables on the grounds are still used. The Monastery Stables' website reads: "Joseph then built a three story mansion, a barn and a paper mill on it. Because of his connection with the Baptists in Ephrata Joseph Gorgas allowed the brothers and sisters from Ephrata to stay with him. This is probably why it's referred to as a monastery."

Built in 1719, the Federal-style Ridgeland Mansion mostly served as a residence for park directors. Now, it's the five-acre headquarters of the Cancer Support Community of Philadelphia, a non-profit that supports cancer patients and their families.

The well-respected astronomer and friend of Ben Franklin was born in this house. It's one of the remaining buildings of Rittenhouse Town, a preserved village that was built in 1690 by David's ancestors and is known as the birthplace of paper in America.

This structure, built in 1715, is also commonly called the Letitia House, after Penn's daughter who is thought to have lived in it. Its origins remain highly contested though, and it wasn't originally located in Fairmount Park, either. The home was moved from Second and Chestnut streets in 1876 to Fairmount for the Centennial's World Fair.

After it was built in the 1760s—via pirate money, no less!— John Adams called this estate, "The most elegant seat in Pennsylvania." The Georgian-style buildings were later owned by war hero and later traitor Benedict Arnold, though he never officially lived here.

Built in 1787, the neoclassical Sweetbriar Mansion was the home of Samuel Breck, a wealthy merchant who purchased 33 acres of land along the Schuylkill. Today, the three-story structure at 1 Sweetbriar Road is currently closed and in need of some repair.

Still standing today, the Federal-style Lemon Hill House was built in 1800 by Philly architect Henry Pratt and served as his country home from 1799 to 1836. On the grounds, Pratt cultivated nearly 3,000 plants for his many gardens. He ultimately sold the home for a mere $225,000 in 1836.

This stunner served as yet another summer retreat for the wealthy. It was built between 1748 and 1750 and originally started out as a small Wissahickon schist stone home. Over the years a number of additions were added, including the porch, a parlor, a kitchen, and a third floor. It was actually moved to Fairmount Park from Frankford neighborhood in the 1920s.

Built between 1756-58 by William Coleman, a Philadelphia merchant and close friend of Benjamin Franklin, this served as another summer home along the Schuylkill. There have only been five owners in the property's history, including the Wharton family. Now it displays 18th- and 19th-century antiques owned by prominent collector Noami Wood.

Built in 1802 by George Plumsted, this Federal-style home sits on a bluff on the Schuylkill River is considered one of the more "modest" country villas of its time. It's a 2.5-story home; it nearly doubled in size from its original build. While it was once poised for demolition after a fire, it has been preserved and now serves as a hostel.

Don't be fooled by the photo: This mansion was built in 1810 and has been restored and preserved. Today it houses the Psychoanalytic Center of Philadelphia, but back then it was another summer villa for owner and dry goods merchant George Thomson. The first floor features a ballroom with floor-to-ceiling windows that look out to the Schuylkill River, and there's a grand staircase in the foyer.

As the story goes, Rebecca Rawle had this home two-story Georgian home built on a land left to her by her widow. The center of the house was built around 1767, and multiple additions followed over the years. The Rawles lost their home when it was seized during the American Revolutionary War, but Rebecca was able to buy it back after.