Philly's newest historic district is 420 Row, a collection of eight ornate homes on the west side of 42nd Street in University City. It was just added to the Philadelphia Register of Historic Places in 2017. The three-story homes were designed and built by G.W. and W.D. Hewitt in the early 1880s, and was the first Queen Anne-style development in Spruce Hill.

Boundaries: 420 to 434 S. 42nd Street

Much of Awbury Arboretum encompasses this district, but it also includes 25-plus structures, many of them that have ties to the prominent Cope family. The Copes first began their purchase of the land in 1849.

Boundaries: Ardleigh Street, E. Haines Street, Devon Place, and Avonhoe Road in Germantown

Also in Germantown is the East Logan Historic District, which was designated historic in 2010. This collection of 30 structures dates back to as early as 1729, when one of the first residences was built. Today, it includes a mix of single-family homes, carriage houses, and industrial buildings, as well as the Hood Cemetery.

Boundaries: From 14 E. Logan Street to the south, 53 E. Logan Street to the west, 213 E. Logan Street to the north, and 92 E. Logan Street to the east.

The Parkside Historic District sits on the edge of Fairmount Park in Philadelphia and dates back to 1890. That's when a group of builders decided to take advantage of the extension of public transportation to the neighborhood and the success of the Centennial Exposition in Fairmount Park. Today, there are numerous architecturally significant structures that line the block of Parkside Avenue, designed by architects like Willis G. Hale (of the Divine Lorraine) and J.C. Worthington, among others.

Boundaries: Parkside Avenue at N. 41st Street to 4262 Parkside Avenue, northwest to 4281 Viola Street, southwest to Viola Street.

Greenbelt Knoll in Northeast Philly started out as a collection of 19 midcentury modern homes—one has been lost since—built in 1956 by Morris Milgram, the leader of the open housing movement in the U.S. It became the first racially integrated housing development in Philly, and one of the first in the country. The neighborhood design was led by Robert Bishop, who was inspired by Frank Lloyd Wright, and Louis Kahn was a consultant.

Boundaries: Surrounded on three sides by Pennypack Park and runs along Longford Street.

Interestingly, Old City, once home to many of America's founding fathers, was not designated a historic district until 2003. The district dates back to as early as 1676, and today is home to some 800 structures that include residences, churches, old banks, institutions, and commercial office buildings—all rich in history.

Boundaries: Independence NationalHistorical Park at the south and west, the Vine Street Expressway at the north, and theDelaware River at the east.

Formerly known as League Island Park, FDR Park was designed in 1912 by Frederick Law Olmsted, Jr., son of the famed landscape architect. As the nomination states, the park features typical Olmsted features: "A wide expanse of field greets visitors as they first enter the park; the flow of each earea is subtly separated for specific activities, and the lack of any one site or piece of architecture is viewed for its individual beauty."

The park is about to undergo a project to remake it into an “urban oasis,” which means—among other things—structural repairs and repaving.

Boundaries: Southwest corner of Broad and Pattison streets, west to 20th Street, east to I-95 to Broad.

This L-shaped South Philly district is named after Stephen Girard, who was once the richest man in the U.S. and the owner of a country home, Gentihommiere, which remains standing. Father and son John and James Windrim designed 421 dwellings on the land beginning in 1906, a mix of styles including Bungalow, Prairie, Mission, Colonial Revival, Jacobean Revival, Tudor Revival, and Craftsman.

Boundaries: Shunk, Porter, South 17th, and South 22d Streets.

The Society Hill Historic District, designated in 1999, contains one of the largest collections of 18th- and 19th-century buildings in the nation, from Colonial to Federal to Georgian dwellings. It has maintained its historic fabric over the years, with very little development, save for a development boom post-World War II that includes the Society Hill Towers by IM Pei. The historic district also includes Washington Square West.

Boundaries: See the official map here.

The Rittenhouse-Fitler Square Historic District has, for the most part, been an exclusive residential neighborhood centered around one of William Penn's original squares. It's rich in architectural history, given that many of the wealthy families who built homes here hired famed architects like John Haviland, Horace Trumbauer, and Frank Furness to design their brownstone mansions. It was one of the first districts that earned historic designation, in 1995.

Boundaries: It's complicated, so here's the official map.

Like its neighboring Diamond Street District (#12), Park Mall (or Park Avenue) was a result of the North Broad industrial boom of the late 19th century. Per the nomination, Park Avenue housed some of the best preserved examples of speculative housing built for the middle classes in North Philly. But today, it's nearly unrecognizable as Liacorous Walk, part of Temple University's campus. The photo above shows the 1800 block of Park Avenue being demolished in 1959 to make way for Liacorous Walk.

Boundaries: 1800 to 1946 Park Avenue

Just five miles from Center City, it's common to feel world's away from Philly when on Main Street in Manayunk. The district was the first to be designated historic in 1984, recognizing the area's historical significance as a town on the Schuylkill River, heavily influenced by the canal to this day. Mill buildings dating back to the 1840s and 1850s remain, while Main Street has become a lively retail and restaurant corridor.

Boundaries: Reading Railroad to the east, Flat Rock Dam to the north, lots 4025-6 to the south, and Schuylkill River to the west.