The American Football League began play in 1909 and was the first professional football circuit. Due to travel constraints (railroads were the primary means of transportation), teams were largely restricted to the northeastern and Midwest United States. During the First Great War, the league was forced to suspend operations, as the draft had scooped up the talent. The AFL resumed play in 1918. The first two decades of the league's existence were turbulent, and not just because of the war. While several teams in large cities -- e.g., the New York Gothams, the Chicago Bears and Cardinals, the Philadelphia Athletics (later the Barrels) -- were mainstays throughout this period, many teams from small markets flitted in and out of the league from season to season. It wasn't until the late '20s that membership stabilized. By 1927, the AFL had 18 teams, arranged into three 6-team divisions.
1927 AFL
East Division: Baltimore Orioles, Brooklyn Bulldogs, Boston Yankees, New York Gothams, Philadelphia Barrels, Washington Warriors
Central Division: Buffalo Braves, Cincinnati Monitors, Cleveland Lakers, Detroit Wolverines, Indianapolis Indians, Pittsburgh Ironmen
West Division: Chicago Bears, Chicago Cardinals, Kansas City Cowboys, Milwaukee Brewers, St. Louis Stallions, St. Paul Saints
The first official "World Bowl" was played that year. The three division winners and the best non-division-winner would face off in Semifinal Games, after which the two victors would participate in the World Bowl to determine the league champion. The World Bowl quickly became very popular; today it has become a de facto holiday across North America.
Meanwhile, the CSA had its own football league, played with CS rules (e.g., no forward passing) and with its own postseason championship game, the Confederate Bowl. The Confederate Football League lasted from 1923 to 1942, when the demands and destruction of war shuttered stadiums all over the country.
1941 CFL
East Division: Atlanta Chiefs, Birmingham Barons, Charleston Patriots, Norfolk Destroyers, Richmond Colts, Savannah Seahawks
West Division: Dallas Rangers, Houston Stars, Memphis Mustangs, Nashville Volunteers, New Orleans Tigers, San Antonio Alamos
The Depression had hit both leagues hard, forcing several franchises to suspend operations. The Second Great War didn't help either. But, as President Smith ordered, the game went on in the US. The Confederate invasion of Ohio and Pennsylvania overran the homes of three AFL teams and placed other stadiums within enemy crosshairs. Undaunted, these teams merely shifted operations to the north, appropriating minor league fields in upstate New York, Wisconsin, Michigan, and Iowa. For instance, the Phil-Pitt Barrelmen actually played in Syracuse, since Pittsburgh had been occupied and Philadelphia's stadium wrecked by CS bombers.
With their rosters depleted, the remaining AFL clubs temporarily merged with one another in order to stay afloat. Physically handicapped players were a common sight on the field. Teams were so desperate for able bodies that they resorted to raiding the roster of Negro League teams. The first black AFL player, Jim Robinson, took the field for the merged New York/Brooklyn team in 1943, and went on to have a Hall of Fame career as a receiver for the Bulldogs.
1943 AFL
East Division: Baltimore/Washington (Rochester), Boston/Buffalo (Boston), New York/Brooklyn (Albany), Philadelphia/Pittsburgh (Syracuse)
West Division: Chicago/Chicago, Detroit/Cleveland (Green Bay), Indianapolis/Cincinnati (Madison), Kansas City/St. Louis (Des Moines), Milwaukee, St. Paul
By 1946, the 18 pre-Depression teams were back in play, most with brand new stadiums rising from the rubble. The West Coast Football League proved an increasingly tough competitor for talent during the '50s.
1952 WCFL: Hollywood Stars, Los Angeles Dons, Oakland Oaks, Portland Columbias (which had briefly renamed themselves the Wolves during the SGW), Sacramento Senators, San Diego Marines, San Francisco Seals, Seattle Sharks
Ultimately, the WCFL lost out to the established league. The AFL absorbed the WCFL in 1961, folding two of its franchises in the process, and realigned into 3 conferences: the Pacific (comprising the former West Coast teams), the Central, and the Atlantic. The number of teams receiving postseason spots was raised from 4 to 8.
1961 AFL
Atlantic Conference
North Division: Boston Yankees, Brooklyn Bulldogs, Buffalo Braves, New York Gothams
South Division: Baltimore Orioles, Philadelphia Barrels, Pittsburgh Ironmen, Washington Warriors
Central Conference
East Division: Cincinnati Monitors, Cleveland Lakers, Detroit Wolverines, Indianapolis Indians
West Division: Chicago Cardinals, Milwaukee Brewers, Minnesota Saints (moved to Minneapolis from St. Paul in 1957), St. Louis Stallions
Pacific Conference
North Division: Portland Columbias, Sacramento Senators, San Francisco Seals, Seattle Sharks
South Division: Denver Bears (from Chicago in 1953), Los Angeles Angels (from KC Cowboys in 1961), Los Angeles Dons, San Diego Marines
Many teams from the old Confederate Football League were reincarnated in the Southern Football League, a minor league which formed in 1954 with clubs in both the US and Texas. Naturally, the league played by US rules, as the old Confederate style had fallen out of favor (and was insufficiently patriotic). The first AFL team from the former CSA, the Habana Hurricanes, had joined in 1969 (along with a new Kansas City Cowboys franchise). The SFL became so popular in the former CSA that the AFL eventually absorbed it in 1984. It became the fourth AFL conference (the Central Conference was renamed the Northern Conference at this time). The number of teams qualifying for the playoffs was upped to 12 that year.
The Canadian Football Association formed in 1958 and consisted of teams in the ex-Canadian provinces and in Quebec. Like the CFL, the CFA also played by American rules. It too was considered a minor league, not on the same level of competition as the AFL. But in 1977, the Toronto Maple Leafs and Vancouver Cougars were deemed worthy and "promoted" to the AFL as expansion teams.
1958-76 CFA
East Division: Montreal Royals, Ottawa Senators, Quebec Capitals, Toronto Maple Leafs
West Division: Calgary Cannons, Edmonton Eskimos, Vancouver Cougars, Winnipeg Wolves
1984 AFL
Atlantic Conference
North Division: Boston Yankees, Brooklyn Bulldogs, Buffalo Braves, New York Gothams, Toronto Maple Leafs
South Division: Baltimore Orioles, Philadelphia Barrels, Pittsburgh Ironmen, Washington Warriors
Northern Conference
East Division: Cincinnati Monitors, Cleveland Lakers, Detroit Wolverines, Indianapolis Indians
West Division: Chicago Cardinals, Kansas City Cowboys, Milwaukee Brewers, Minnesota Saints, St. Louis Stallions
Southern Conference
East Division: Atlanta Chiefs, Birmingham Barons, Habana Hurricanes, Miami Seahawks (from Savannah in 1966), Richmond Colts
West Division: Dallas Rangers, Houston Stars, Memphis Mustangs, New Orleans Tigers
Pacific Conference
North Division: Portland Columbias, Sacramento Senators, San Francisco Seals, Seattle Sharks, Vancouver Cougars
South Division: Denver Bears, Los Angeles Angels, Los Angeles Dons, San Diego Marines
The most recent round of expansion occurred in 2001, when 4 new teams were added, bringing the total number of teams up to its current 40. The postseason was also expanded that year to 16 teams.
2001 AFL
Atlantic Conference
North Division: Boston Yankees, Buffalo Braves, Montreal Royals, Ottawa Ospreys, Toronto Maple Leafs
South Division: Baltimore Orioles, Brooklyn Bulldogs, New York Gothams, Philadelphia Barrels, Washington Warriors
Northern Conference
East Division: Cincinnati Monitors, Cleveland Lakers, Detroit Wolverines, Indianapolis Indians, Pittsburgh Ironmen
West Division: Chicago Cardinals, Kansas City Cowboys, Milwaukee Brewers, Minnesota Saints, St. Louis Stallions
Southern Conference
East Division: Atlanta Chiefs, Charlotte Hornets, Habana Hurricanes, Miami Seahawks, Richmond Colts
West Division: Birmingham Barons, Dallas Rangers, Houston Stars, Memphis Mustangs, New Orleans Tigers
Pacific Conference
North Division: Portland Columbias, Sacramento Senators, San Francisco Seals, Seattle Sharks, Vancouver Cougars
South Division: Denver Bears, Los Angeles Angels, Los Angeles Dons, San Diego Marines, Tucson Sidewinders