An independent baseball league is a professional baseball organization located in the United States or Canada that is not operated in conjunction with either a Major League Baseball team or an affiliated Minor League Baseball team. Being independent allows teams to be located close to major league teams without their consent. Such leagues have been around for many years and were once known as "outlaw leagues" due to their position outside the rules of affiliated minor league baseball.
The Northern League and Frontier League both started play in 1993, and the Northern League's success paved the way for other independent leagues like the Texas-Louisiana League and Northeast League. The Atlantic League has had more marquee players than any other independent league, including Jose Canseco, Rickey Henderson, Ozzie Canseco, Rubén Sierra, Carlos Baerga, and John Rocker. The Northern League alumni include Leon "Bull" Durham, J. D. Drew, and Darryl Strawberry.
Independent leagues have flourished in northeastern states, where dense populations can often support multiple franchises. Because they are not subject to the territorial limitations imposed on affiliated minor-league teams, independent clubs can relocate as close to affiliated teams (and one another) as they choose to. For example, the city of Lancaster, Pennsylvania cannot have an affiliated team because of its proximity to the Harrisburg Senators and Reading Fightin Phils, leaving the Atlantic League to place a team—the Lancaster Barnstormers—to fill the void. Another example is the greater New York City metropolitan area, where there are many independent teams: the Long Island Ducks, New Jersey Jackals, Rockland Boulders, and Sussex County Miners. The Kansas City area is home not only to the American League's Kansas City Royals, but also the independent Kansas City Monarchs.