Park Avenue runs north and south between Madison Avenue and Lexington Avenue in Manhattan in New York City. It is noted for its perennially high real estate prices along much of its length, especially the Upper East Side. From 40th Street to 60th Street, Park Avenue runs through Midtown Manhattan and is distinguished by its glass box skyscrapers, many of which serve as corporate headquarters for corporations such as J.P. Morgan Chase, Bear Stearns, and Met Life.

Park Avenue was originally known as "Fourth Avenue" and carried the tracks of the New York and Harlem Railroad starting in the 1830s. In the 1850s, the tracks north of 14th Street were sunk out of sight in a tunnel whose roof was covered with grates and grass. This long, grass-roofed tunnel was the "park" of Park Avenue, and the name was changed at that time. At 97th Street, the tracks emerge from underground and north of that point, the Park Avenue Viaduct runs above the avenue, carrying commuter rail service for Metro-North Railroad.

The avenue retains the name "Fourth Avenue" between 8th and 14th Streets, and the name "Lafayette Place" south of 8th Street. From 14th Street to 17th Street, it is also known as "Union Square East", as it borders Union Square.

With the building of Grand Central Station, the section of Park Avenue south of 42nd Street became known as "Park Avenue South". In 1936, a bridge was built over the station to allow automobile traffic to pass the station unimpeded. In 1963, the Pan Am Building was built straddling Park Avenue atop Grand Central Station, with a tunnel through it to accommodate the automobile bridge.

Park Avenue is also the name of a Dublin 4, Ireland, road joining Sidney Parade Avenue to the south and Gilford Road in Sandymount to the North. It is home to a number of cricket and rugby grounds. Of architectural note is the Church of St. John (Church of Ireland), noted for its French Bath stone's decay due to its proximity to the sea.

Interestingly, Park Avenue, Dublin 4 is also noted for its perennially high property prices.