Defunct professional sports leagues in the United States

The Prairie League was an independent league of baseball which was based in the prairie provinces of Saskatchewan and Manitoba and the states of North Dakota, South Dakota, Minnesota and Wisconsin. The league was original in its naming by choosing not to resurrect a name previously used by a defunct minor league. The professional eight-team league was founded in 1995 following the demise of the North Central League. Having produced several major league prospects, it ceased operations after the 1997 season due to financial troubles and lack of interest in cities.

The Continental Basketball League (CBL) was a men's basketball minor league in the United States that began play in April 2010. The league is headquartered in Florida.

The Kentucky–Illinois–Tennessee League (or KITTY League) was a Class D minor league baseball circuit that went through six different lives. The first KITTY League played from 1903 through 1906. The next one ran from 1910 through 1914. The third try played a single season (1916). The circuit was revived in 1922 and lasted three years. The fifth KITTY League lasted the longest, playing from 1935 through 1955 with a break from 1943 to 1945 due to World War II. The league was also known briefly as the Kentucky–Indiana–Tennessee League, for during this time the league contained teams such as the Evansville Yankees from Evansville, Indiana. Unlike most leagues that were dormant for years in between playing, the KITTY was much the same from 1903 to 1955, through its inactive years. Clifton C. Gosnell was league president in 1906, after which the league stopped playing, and was president in 1910–1911 when play resumed. Then Dr. Frank H. Bassett was league president 1912–1914, 1916, 1922–1924, and 1935–1937, through the active times and the inactive. Hopkinsville, Kentucky was represented for 28 of the 31 active seasons of the KITTY League, while Paducah, Kentucky made it for 23.

The Negro American League was one of the several Negro leagues created during the time organized American baseball was segregated. The league was established in 1937, and disbanded after its 1962 season.

The New York Pro Football League (NYPFL) was a professional American football league, active in the 1910s, and based in upstate New York, primarily Western New York. Between 1920 and 1921, the league's best teams were absorbed into the National Football League, though none survive in that league today. It was one of the biggest challengers to the Ohio League in professional football in the 1910s.

The Continental Basketball Association (CBA) (also known as the Eastern Pennsylvania Basketball League, the Eastern Professional Basketball League, and the Eastern Basketball Association) was a men's professional basketball minor league in the United States from 1946 to 2009.

The XFL is a planned professional American football league owned by Vince McMahon's Alpha Entertainment, and is headquartered in Stamford, Connecticut. It is the successor to the previous XFL, which was controlled by the World Wrestling Federation (WWF, now WWE) and NBC, and ran for a single season in 2001. The league will follow a similar structure as the original XFL did in 2001, with eight teams, centrally owned and operated by the league (as opposed to the franchise model, with each team having different ownership groups) and spread across the United States in markets currently or recently represented by a National Football League (NFL) franchise, competing in a ten-game season and a two-week postseason in the winter and spring months, after Super Bowl LIV.

The North American League (officially known as the North American Baseball League) was an independent baseball league that began play in the 2011 season. The league consisted of a merger of three independent leagues, the Northern League of Illinois, United League Baseball of Texas, and the Golden Baseball League based in the Western United States and Western Canada and was a last-ditch effort to save the teams in said league. The league's chairman of the board was Dave Kaval, former CEO of Diamond Sports and Entertainment (owners of the now-defunct GBL), league president was Brian MacInnes and main board member was James C. Peters.

The Ohio League was an informal and loose association of American football clubs active between 1902 and 1919 that competed for the Ohio Independent Championship (OIC). As the name implied, its teams were mostly based in Ohio. It is the direct predecessor to the modern National Football League (NFL).

Women's Professional Soccer (WPS) was the top level professional women's soccer league in the United States. It began play on March 29, 2009. The league was composed of seven teams for its first two seasons and fielded six teams for the 2011 season, with continued plans for future expansion. The WPS was the highest level in the United States soccer pyramid for the women's game.