Madison Square Garden, often abbreviated as MSG, has been the name of four arenas in New York City, United States. The first two were located at Madison Square, thus the name. Subsequently a new 20,000-seat Garden was built at 50th Street and 8th Avenue, and the current Garden is sited on top of Pennsylvania Station at 33rd Street and 7th Avenue.

The present Garden is best known as the home of the New York Knicks (basketball) and New York Rangers (ice hockey), professional sports teams that play their home matches in the arena. It also hosts the Ringling Brothers and Barnum and Bailey Circus when it comes to New York City and almost any other kind of indoor activity that draws large audiences, such as the 2004 Republican National Convention.

MSG is also known for its place in the history of boxing. Many of boxing's most important fights were held at the Madison Square Garden, including many of Joe Louis, the Roberto Duran-Ken Buchanan affair, and the first Joe Frazier-Muhammad Ali bout. Before promoters such as Don King and Bob Arum moved boxing to Las Vegas, the Madison Square Garden was considered the Mecca of boxing.

Seating in the present Madison Square Garden is arranged in five ascending levels. The lowest one is referred to as "rink-side" for hockey games or "court-side" for basketball games (at some events a still lower seating level, known as the Rotunda, is also provided); next above this is the First Promenade, followed by the Second Promenade, First Balcony and Second Balcony. The seats of these five levels originally bore the colors red, orange, yellow, green and blue respectively; however, this color scheme has since been abolished, mainly because the "blue seats" had become synonymous with rowdy behavior by fans, particularly those attending New York Rangers hockey games.

The site of the first Madison Square Garden was formerly the Union Depot of the New York and Harlem Railroad. When the depot was moved to the current site of Grand Central Terminal in 1871 the depot was sold to P.T. Barnum and converted into hippodrome called "Barnum's Monster Classical and Geological Hippodrome". In 1876 it was renamed to Gilmore's Garden.

William Henry Vanderbilt officially renamed Gilmore's Garden to Madison Square Garden and reopened the facility to the public on May 30, 1879 at 26th Street and Madison Avenue. The first arena was originally built for the sport of track cycling, which is still remembered in the name of the Madison event.

The second Madison Square Garden, designed by Stanford White, who would later be killed there, opened at this site in 1890 and remained until the third Garden opened in 1925. On February 11, 1968 Madison Square Garden III closed and Madison Square Garden IV opened.

Notable Firsts at Madison Square Garden

• February 12, 1879 - The first artificial ice rink in North America opened at the Garden.
• 1902 - The first indoor professional American football game is played
• 1934 - The first college basketball game at the Garden is played, between the University of Notre Dame and New York University
• February 28, 1940 - Basketball is televised for the first time (Fordham University vs. the University of Pittsburgh)
• March 19, 1954 - Joey Giardello knocked out Willie Tory in round seven at the Garden in the first televised prize boxing fight shown in color.
• March 31, 1985 the WWF, now known as the WWE presented the first WrestleMania Pay Per View event, marketed as the Greatest spectacle in professional wrestling, revolutionizing the Sports Entertainment industry.
• June 14, 1994 - After 54 years the New York Rangers win the Stanley Cup at Madison Square Garden.

Notable other events at Madison Square Garden

• June 25, 1906 - Architect Stanford White is assassinated by Harry K. Thaw on the rooftop, allegedly because he seduced the murderer's wife, Evelyn Nesbit.