Park Slope faced social and infrastructural decline in the mid-20th century, but the building stock was renovated after the area became gentrified starting in the 1960s.

The Lenape typically lived in wigwams, and had larger fishing and hunting communities near freshwater sites on higher land.

[15][16] The first European settlement occurred in 1637-1639 when Willem Kieft, the Dutch West India Company's director, purchased almost all land in what is now Brooklyn and Queens.

[15] During the American Revolutionary War, on August 27, 1776, the Park Slope area served as the backdrop for the beginning of the Battle of Long Island.

[18][19][20] The Battle Pass site is now preserved in Prospect Park,[21][22] while on Fifth Avenue, there is a reconstruction of the Old Stone House, a farmhouse where a countercharge covered the American retreat.

[33] By the late 1870s, with horse-drawn rail cars running to the park and the ferry, bringing many rich New Yorkers in the process, urban sprawl dramatically changed the neighborhood into a streetcar suburb.

[50] By 1883, with the opening of the Brooklyn Bridge, Park Slope continued to boom and subsequent brick and brownstone structures pushed the neighborhood's borders farther.

As the New York Tribune wrote in 1899, "Nature set the park down where it is, and man has embellished her work in laying out great lawns and artificial lakes, in bringing together menageries and creating conservatories, in making roads and driveways, and in doing everything in his power to make the place a pleasant pleasure ground and a charming resort.

[53] Following Brooklyn's subsumption into the City of Greater New York in 1898 and accelerating in the 1910s, many wealthy and upper middle-class families fled for the suburban life, initially to outlying Brooklyn and Queens neighborhoods (such as nearby Flatbush) and thence to more distant locales in Westchester County, Nassau County and New Jersey amid the adoption of the automobile.

Manhattan gained economic and cultural dominance in the consolidated city, helped by transportation improvements like the subway, which brought a more heterogeneous population to Brooklyn.

The socioeconomic changes were slowed by the ongoing development of upscale apartment houses on Prospect Park West and Plaza Street along with infill middle-class buildings throughout the neighborhood.

Only a fraction of the area, centered in the traditional Gold Coast district and select adjoining blocks, retained wealthy and upper middle-class residents into the 1940s.

[55] While the building attracted such notable residents as pharmaceutical executive John L. Smith and remained a "solid fortress of wealth" for decades, it ultimately failed to anchor comparable development in the neighborhood.

Some of those that remained reacted violently to the ethnic changes to the neighborhood; for example, white residents of Park Slope attempted to bar African-Americans from participating in after-school programs at William Alexander Middle School in 1966.

One of the airplanes, a Douglas DC-8 operated by United Airlines, was able to stay airborne for a few miles before crashing near the corner of Sterling Place and Seventh Avenue.

[64] Young professionals began to buy and renovate brownstones (which only cost around $15,000–35,000 at the time), often converting them from rooming houses into single and two-family homes.

[65] Preservationists helped secure landmark status for many of the neighborhood's blocks of historic row houses, brownstone, and Queen Anne, Renaissance Revival, and Romanesque mansions.

After the 1973 creation of the landmark district, primarily above 7th Avenue, the rate of gentrification was sped up, and throughout the 1970s, the area saw an influx of young professional couples.

Following decades of socioeconomic precarity, the influx of the upper middle class has returned Park Slope to its Gilded Age milieu as one of the wealthiest neighborhoods in Brooklyn—and the nation.

Much of the neighborhood is composed of rowhouses and six-to-eight-story apartment buildings, though Fourth, Fifth and Seventh Avenues contain residential structures with commercial space on the ground floors.

[76] Containing 2,575 buildings stretching over part or all of around 40 city blocks, the historic district is New York's largest landmark neighborhood.

[90][91] Based on data from the 2020 United States Census, the population of the Park Slope–Gowanus neighborhood tabulation area (NTA) was 74,731 a change of 7082 (10.46%) from the 67,649 counted in 2010.

[95] In 2018, an estimated 10% of Park Slope and Carroll Gardens residents lived in poverty, compared to 21% in all of Brooklyn and 20% in all of New York City.

[92]: 14 The concentration of fine particulate matter, the deadliest type of air pollutant, in Park Slope and Carroll Gardens is 0.0089 milligrams per cubic metre (8.9×10−9 oz/cu ft), higher than the citywide and boroughwide averages.

[104] The United States Post Office operates three locations nearby: Park Slope is considered one of New York City's most desirable neighborhoods.

[108] It was named one of the "Greatest Neighborhoods in America" by the American Planning Association in 2007, "for its architectural and historical features and its diverse mix of residents and businesses, all of which are supported and preserved by its active and involved citizenry.

"[109] In December 2006, Natural Home magazine named Park Slope one of America's ten best neighborhoods based on criteria including parks, green spaces and neighborhood gathering spaces; farmers' markets and community gardens; public transportation and locally owned businesses; and environmental and social policy.

[118] Park Slope is home to a wide variety of religious institutions, or houses of worship, including many churches and synagogues; most are historic buildings, and date back many decades.

Synagogues include:[121] Park Slope and Carroll Gardens generally have a much higher ratio of college-educated residents than the rest of the city as of 2018[update].

[126] Park Slope and Carroll Gardens's rate of elementary school student absenteeism is lower than the rest of New York City.