It is the largest borough geographically and is adjacent to the borough of Brooklyn. To its east is Nassau County. Queens also shares water borders with the boroughs of Manhattan and the Bronx. The borough of Queens is the second-largest in population (after Brooklyn).

Queens is one of the most ethnically diverse counties in the United States, as well as the most diverse among highly populated counties and the most linguistically diverse place on Earth.

The Long Island Rail Road is the busiest commuter railroad in North America and operates 24/7. Nassau County high school students often feature prominently as winners of the Intel International Science and Engineering Fair and similar STEM-based academic awards. Biotechnology companies and scientific research play a significant role in Long Island's economy, including research facilities at Brookhaven National Laboratory, Cold Spring Harbor Laboratory, Plum Island Animal Disease Center, State University of New York at Stony Brook, the New York University Tandon School of Engineering, the City University of New York, and Hofstra Northwell School of Medicine.

The East Bronx has older tenement buildings, low income public housing complexes, and multifamily homes, as well as single family homes. It includes New York City's largest park: Pelham Bay Park along the Westchester-Bronx border.

City Island is located east of Pelham Bay Park in Long Island Sound and is known for its seafood restaurants and private waterfront homes. City Island's single shopping street, City Island Avenue, is reminiscent of a small New England town. It is connected to Rodman's Neck on the mainland by the City Island Bridge.

The western parts of the Bronx are hillier and are dominated by a series of parallel ridges, running south to north. It includes New York City's third-largest park: Van Cortlandt Park along the Westchester-Bronx border. The Grand Concourse, a wide boulevard, runs through it, north to south.

Brooklyn hosts the world-renowned Brooklyn Academy of Music, the Brooklyn Philharmonic, and the second-largest public art collection in the United States, housed in the Brooklyn Museum.

The Brooklyn Museum, opened in 1897, is New York City's second-largest public art museum. It has in its permanent collection more than 1.5  a million objects, from ancient Egyptian masterpieces to contemporary art. The Brooklyn Children's Museum, the world's first museum dedicated to children, opened in December 1899. The only such New York State institution accredited by the American Alliance of Museums, it is one of the few globally to have a permanent collection – over 30,000 cultural objects and natural history specimens.

Cities in Westchester have many well established sub-areas within the municipal boundaries. Many of these are similar to hamlets and date back to as early as the late 1600s such as Cooper's Corners in New Rochelle. These areas also include some of the first planned communities in the country such as New Rochelle's Residence Park, Rochelle Park and Heights and Sutton Manor.

The Timothy Knapp House, built around 1670, is the oldest standing building in Westchester. Philipse Manor Hall and the Old Dutch Church of Sleepy Hollow are also among the oldest, built around 1682 and 1685 respectively. Philipse Manor Hall is located in Getty Square, Yonkers, and is operated by the New York State Office of Parks, Recreation and Historic Preservation.