By Bill Turianski on 29 May 2019; twitter.com/billsportsmaps.

Sources:
-Baseball-Reference.com, 1926 AL season; 1926 NL season.
-SportsLogos.net.
-Baseball Hall of Fame’s Dressed to the Nines (uniforms illustrated by Marc Okkonen), exhibits.baseballhalloffame.org/[Dressed to The Nines database].
-US cities’ populations (1920 figures), biggestuscities.com/1920.
-Attendances. Source: baseball-reference.com/leagues/MLB/1926-misc.shtml.

Links…
-An article on the St. Louis Cardinals circa 1926 to 1934…1926-34: The St. Louis Cardinals Were as Dominant as the Great Yankees Teams (by Harold Friend at bleacherreport.com).
-An article on Rogers Hornsby, who has the 2nd-best all-time Batting Average in MLB history (at .358, which is second only to Ty Cobb’s .367 BAvg)…Rogers Hornsby (by C. Paul Rogers III at sabr.org). {Excerpts: ‘Any conversation about the greatest hitter in baseball history must include Rogers Hornsby…’ …‘Although the assessment seems rather harsh given the competition, Bill James has characterized Hornsby as perhaps the biggest “horse’s ass” in baseball history, ahead of even Ty Cobb’.}
-An article on Grover Cleveland Alexander…Alexander provides ultimate relief for Cardinals in 1926 World Series (by Craig Muder at baseballhall.org).

-Here is a link to my map-and-post of 1925 MLB: 1925 Major League Baseball: Map with logos & uniforms. Including final standings, top players, and attendance + 1925 World Series winners: Pittsburgh Pirates. That post (from April 2019) also contains descriptions of the map template used there (and here), as well as a city-by-city look at Major League attendance from the 1920s.

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From 1903 to 1952 (50 seasons), there were no franchise-shifts in Major League Baseball. The 16 MLB teams from this 50-year period played in only 9 American cities…New York City (3 teams), Chicago (2 teams), Philadelphia (2 teams), Detroit, Cleveland, St. Louis (2 teams), Boston (2 teams), Pittsburgh, Washington, and Cincinnati.

Below: a chart of 1920s USA city populations, with 1926 MLB teams noted…

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In 1926, led by player/manager Rogers Hornsby, the St. Louis Cardinals defeated the New York Yankees in 7 games, to win their first World Series title. The Cardinals have won the second-most World Series titles, 11 (their last being in 2011). Those eleven World Series titles won by St. Louis are second only to the 27 titles won by the New York Yankees.

1926 MLB stats leaders…
ERA: Lefty Grove (Philadelphia Athletics).
Wins: George Uhle (Cleveland Indians).
BAvg: Heinie Manush (Detroit Tigers).
HR: Babe Ruth (New York Yankees).
RBI: Babe Ruth (New York Yankees).
OPS: Babe Ruth (New York Yankees).
WAR: Babe Ruth.(New York Yankees)
WAR for pitchers: George Uhle (Cleveland Indians).
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Photo and Image credits on the map page…
1926 WS champions St Louis Cardinals (banner)…
Shoulder-patch crest, from hofmwholesale.com. 1926 STL cap, from dugout-memories.com. 1926 STL WS ring, from pinterest.com. 1926 WS [Sportsman's Park] program, from baseball-almanac.com/ws/yr1926.
Rogers Hornsby [photo circa 1926], unattributed at rogershornsby.com. Rogers Hornsby [1961 Golden Press card] from amazon.com. Les Bell [photo from 1926], gettyimages.com. Bob O’Farrell [photo circa 1926], unattributed at sabr.org. Ray Blades [photo circa 1930], photo by Sporting News and Rogers Photo Archive via gettyimages.com. Jim Bottomley [photo circa 1925], unattributed at baseballhall.org/hall-of-famers/bottomley-jim. Bill Sherdel [photo from 1929], photo by Sporting News and Rogers Photo Archive via gettyimages.com.

1926 MLB stats leaders…
Lefty Grove (PHA) [photo from 1925], photo by Charles M Conlon via sports.mearsonlineauctions.com. George Uhle (CLE) [photo from 1926], photo by George Rinhart/Corbis via gettyimages.ca. George Uhle (CLE) [photo from 1927], photo by Sporting News and Rogers Photo Archive via gettyimages.co.uk. Heinie Manush (DET) [photo circa 1924], unattributed at findagrave.com. Babe Ruth (NYY) [photo circa 1925], unattributed at pinterest.com. Babe Ruth (NYY) [colorized photo circa 1926], unattributed/colorized by Jecinici via reddit.com/r/yankees.

-Colorized photo of Philadelphia Athletics 1925-27 elephant-logo jersey, photo unattributed and colorized by Natalia Valiukevich/mediadrumworld.com via dailymail.co.uk/article.
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Thanks to all at the links below,
-University of Texas at Austin online archive (Perry-Castañeda Library Map Collection), legacy.lib.utexas.edu/maps/united_states.html.
-Baseball-Reference.com, 1925 AL season; 1925 NL season.
-Major League Baseball (en.wikipedia.org).
-SportsLogos.net.
-Baseball Hall of Fame’s Dressed to the Nines (uniforms illustrated by Marc Okkonen), exhibits.baseballhalloffame.org/dressed_to_the_nines/database.htm.
-MLB.cm/shop.
-US cities’ populations (1920 figures), biggestuscities.com/1920.