The American Indoor Soccer Association (AISA) formed in 1984 as a Midwest-based indoor soccer circuit.   The league was a second tier effort by design, playing primarily in small minor league hockey arenas in cities such as Canton, Columbus, Kalamazoo and Milwaukee.  Early AISA players typically aspired to move up to the Major Indoor Soccer League, which offered highest level of professional soccer in the United States (indoor or outdoor) from 1984 through the end of the decade.

In the late 1980′s the AISA began to expand its geographic footprint and to lease higher quality arenas.  To reflect its new sense of ambition, the league re-branded itself as the National Professional Soccer League prior to the 1990-91 season.   The league also began to tinker with traditional indoor soccer scoring rules (which awarded one point for each goal) in the  late 1980′s, creating 2-point and 3-point goals for scoring from distance, as well as distinctions between the value of full strength and power play goals.  By the 1990′s, double-digit scores were the norm in NPSL games.

The league continued to expand aggressively in the 1990′s, placing franchises from Florida to Denver to Montreal.  But the overall fortunes of the sport were in decline and the NPSL terminated operations at the end of the 2000-01 season.  Six NPSL franchises soldiered on for a while in successor leagues.

Two former NPSL clubs are still in operation as of 2012, including the Milwaukee Wave who began play as an original AISA franchise in the winter of 1984.  The other surviving club is the Baltimore Blast.

==Franchise List==