Key Arena at Seattle Center is located north of downtown Seattle, USA on the grounds of Seattle Center (the site of 1962's Century 21 Exposition, a World's Fair). The arena's primary tenants are the Seattle SuperSonics of the National Basketball Association. It hosted the 1974 NBA All-Star Game.

The arena was opened in 1962 as the Seattle Center Coliseum. It was completely rebuilt in between 1994 and 1995. The building's original roofline was used as a guide, but almost everything about the arena was brand new aside from the roof trusses and some of the original concrete supports. The court was lowered 35 feet (10.5 meters) below street level to allow for 3,000 more seats. After the rebuild, the Coliseum was renamed KeyArena, as Key Bank purchased the naming rights. The first regular season game that the Seattle SuperSonics played in the rebuilt arena was on November 4, 1995, against the Los Angeles Lakers.

For several seasons between 1980-1985, the Sonics used the Kingdome as their home arena, in addition to the Coliseum. This primarily occurred during playoff games and other games with sellout crowds exceeding that of the old coliseum's capacity of around 14,000. The Coliseum has also been a site of controversy. On January 5, 1986, a game between the Sonics and the Phoenix Suns was rained out on account of a leaky roof. Several seasons before in 1972, Spencer Haywood injured himself after slipping in a water puddle on court as a result of the leaky roof. He would later sue the City of Seattle and collect $55,000.[1]

In addition to being the home of the Sonics, it is also home to the Seattle Storm of the Women's National Basketball Association and the Seattle Thunderbirds, a junior hockey team in the Western Hockey League. The Thunderbirds hosted the Memorial Cup here in 1992. It is also used for non-athletic entertainment purposes, such as ice shows, circuses, and concerts.

The renovation cost the city of Seattle $74.5 million, and the Seattle SuperSonics approximately $21 million. KeyArena is the first publicly financed arena fully supported by earned income from the building. Its seating capacity for basketball games is 17,072, ice hockey games and ice shows 15,177, end-stage concerts 16,641, and center-stage concerts and boxing 17,459. Risers hold 7,440 on the upper level and up to 7,741 on the lower level, with luxury suites adding another 1,160 seats.

In late 2004 proposals for expanding KeyArena to nearly twice its current size to accommodate new restaurants, shops, and a practice court (the cost is to be approximately $220 million) were debated.

On March 6, 2008 Seattle's Mayor announced that a local ownership group involving Microsoft CEO Steve Balmer made a "game changing" commitment to invest $150 million in cash towards a $300 million renovation of Key Arena and are ready to purchase the Seattle SuperSonics in order to keep them in the City of Seattle.