The Eastern State Penitentiary is a former prison in Philadelphia. The penitentiary refined the revolutionary system of separate incarceration (known as the Pennsylvania system), which emphasized principles of reform rather than punishment. When the Eastern State Penitentiary was erected in 1829, it was the largest and most expensive public structure in the country. The prison was closed and abandoned in 1971, as it became too expensive to maintain. It now is open as a museum, but is minimally maintained, making it an exciting place for a photographer.

Laurel Hill Cemetery, in Philadelphia, Pennsylvania, is the second major garden or rural cemetery in the United States. It was designated a National Historic Landmark in 1998, one of only a few cemeteries to receive the distinction.

The cemetery has spectacular vistas and thousands of 19th- and 20th-century marble and granite funerary monuments on 74 acres (300,000 m2) terraced above the Schuylkill River in Philadelphia's East Falls section. Obelisks dot the rolling terrain, which is highlighted by elaborately sculpted hillside tombs and mausoleums. Overall, Laurel Hill contains more than 33,000 monuments and more than 11,000 family lots. (Wikipedia http://en.wikipedia.org/wiki/Laurel_Hill_Cemetery ; official site http://www.thelaurelhillcemetery.org/ )

A small settlement a few miles north of Philadelphia, Bryn Athyn is famous for its neo-Gothic cathedral, the Episcopal seat of the General Church of the New Jerusalem (or just New Church). Next to the cathedral are Cairnwood and Glencairn, the mansions of John Pitcairn and his son Raymond. Glencairn now holds a museum of mostly religious artwork.

Chanticleer is an exquisite garden located in Wayne, PA. According to the Washington Post, Chanticleer is one of the most interesting and edgy public gardens in America. Adolph Rosengarten, Jr., whose family firm became part of the Merck & Company, left the Chanticleer estate for the enjoyment and education of the public.
More pictures at http://public.fotki.com/OlegSokol/photoshoots/chanticleer/

One of the oldest arboreta in the northeastern United States, Tyler Arboretum encompasses 650 acres of renowned plant collections, champion trees, historic buildings, and 20 miles of hiking trails through woodlands, wetlands, and meadows.

A beautiful quiet sunset on a lake about an hour west of Philadelphia.

In 1704, Nathaniel and Mary Newlin built a water-powered grist mill along the West Branch of Chester Creek. Despite several changes of ownership the mill ran continuously until 1941. In 1957, the Nicholas Newlin Foundation was created by E. Mortimer Newlin, a ninth generation descendant, to restore and maintain the mill as a museum. Today, the foundation 's purpose is to preserve the 150 acres, which are a refuge for plants, animals, and birds, as well as the park's historic buildings for pleasure and education of the public. A trip to the park offers visitors insights into the vanished life of the rural eighteenth century.
http://www.newlingristmill.org/

Nemours is the estate of Alfred duPont. It consists of a mansion surrounded by a variety of gardens, including French parterre Boxwood gardens, a maze garden with a reflecting pool, formal Sunken garden (indeed artificially lowered to provide unobstructed view of the Temple of Love from the mansion).

Winterthur, an American country estate, is the former home of Henry Francis du Pont (1880-1969), an avid antiques collector and horticulturist.

Swarthmore college in Media, a suburb to the South-West of Philly, is more like a park than a campus.