| Franchise ID | Team ID | Full Team Name | First Year | Last Year |
| ALT | ALT | Altoona Mountain City | 1884 | 1884 |
| ANA | ANA | Los Angeles Angels of Anaheim | 1997 | Present |
| ANA | CAL | California Angels | 1965 | 1996 |
| ANA | LAA | Los Angeles Angels | 1961 | 1964 |
| ARI | ARI | Arizona Diamondbacks | 1998 | Present |
| ATH | ATH | Philadelphia Athletics | 1876 | 1876 |
| ATL | ATL | Atlanta Braves | 1966 | Present |
| ATL | BSN | Boston Braves | 1876 | 1952 |
| ATL | MLN | Milwaukee Braves | 1953 | 1965 |
| BAL | BAL | Baltimore Orioles | 1954 | Present |
| BAL | MLA | Milwaukee Brewers | 1901 | 1901 |
| BAL | SLB | St. Louis Browns | 1902 | 1953 |
| BFB | BUF | Buffalo Bisons | 1890 | 1890 |
| BFL | BUF | Buffalo Blues | 1914 | 1915 |
| BLC | BAL | Baltimore Lord Baltimores | 1872 | 1874 |
| BLO | BAL | Baltimore Orioles | 1882 | 1891 |
| BLO | BLN | Baltimore Orioles | 1892 | 1899 |
| BLT | BAL | Baltimore Terrapins | 1914 | 1915 |
| BLU | BLU | Baltimore Monumentals | 1884 | 1884 |
| BNA | BOS | Boston Red Stockings | 1871 | 1875 |
| BOS | BOS | Boston Red Sox | 1901 | Present |
| BRA | BRA | Brooklyn Atlantics | 1872 | 1875 |
| BRD | BOS | Boston Reds | 1884 | 1884 |
| BRG | BRG | Brooklyn Gladiators | 1890 | 1890 |
| BRS | BOS | Boston Reds | 1890 | 1891 |
| BTT | BTT | Brooklyn Tip-Tops | 1914 | 1915 |
| BUF | BUF | Buffalo Bisons | 1879 | 1885 |
| BWW | BWW | Brooklyn Ward's Wonders | 1890 | 1890 |
| CBK | COL | Columbus Buckeyes | 1883 | 1884 |
| CBL | CLV | Cleveland Blues | 1879 | 1884 |
| CEN | CEN | Philadelphia Centennials | 1875 | 1875 |
| CFC | CLE | Cleveland Forest Citys | 1871 | 1872 |
| CHC | CHC | Chicago Cubs | 1876 | Present |
| CHH | CHI | Chicago Whales | 1914 | 1915 |
| CHP | CHI | Chicago Pirates | 1890 | 1890 |
| CHW | CHW | Chicago White Sox | 1901 | Present |
| CIN | CIN | Cincinnati Reds | 1882 | Present |
| CKK | CKK | Cincinnati Kelly's Killers | 1891 | 1891 |
| CLE | CLE | Cleveland Indians | 1901 | Present |
| CLI | CLE | Cleveland Infants | 1890 | 1890 |
| CLS | COL | Columbus Solons | 1889 | 1891 |
| CLV | CLE | Cleveland Blues | 1887 | 1888 |
| CLV | CLV | Cleveland Spiders | 1889 | 1899 |
| CNA | CHI | Chicago White Stockings | 1871 | 1875 |
| CNR | CIN | Cincinnati Reds | 1876 | 1880 |
| COL | COL | Colorado Rockies | 1993 | Present |
| COR | COR | Cincinnati Outlaw Reds | 1884 | 1884 |
| CPI | CPI | Chicago/Pittsburgh (Union League) | 1884 | 1884 |
| DET | DET | Detroit Tigers | 1901 | Present |
| DTN | DTN | Detroit Wolverines | 1881 | 1888 |
| ECK | ECK | Brooklyn Eckfords | 1872 | 1872 |
| FLA | FLA | Florida Marlins | 1993 | 2011 |
| FLA | MIA | Miami Marlins | 2012 | Present |
| HAR | HAR | Hartford Dark Blues | 1876 | 1877 |
| HNA | HAR | Hartford Dark Blues | 1874 | 1875 |
| HOU | HOU | Houston Astros | 1962 | Present |
| IBL | IND | Indianapolis Blues | 1878 | 1878 |
| IHO | IND | Indianapolis Hoosiers | 1884 | 1884 |
| IND | IND | Indianapolis Hoosiers | 1887 | 1889 |
| KCC | KCC | Kansas City Cowboys | 1888 | 1889 |
| KCN | KCN | Kansas City Cowboys | 1886 | 1886 |
| KCP | KCP | Kansas City Packers | 1914 | 1915 |
| KCR | KCR | Kansas City Royals | 1969 | Present |
| KCU | KCC | Kansas City Cowboys | 1884 | 1884 |
| KEK | KEK | Fort Wayne Kekiongas | 1871 | 1871 |
| LAD | BRO | Brooklyn Dodgers | 1884 | 1957 |
| LAD | LAD | Los Angeles Dodgers | 1958 | Present |
| LGR | LOU | Louisville Grays | 1876 | 1877 |
| LOU | LOU | Louisville Colonels | 1882 | 1899 |
| MAN | MAN | Middletown Mansfields | 1872 | 1872 |
| MAR | MAR | Baltimore Marylands | 1873 | 1873 |
| MIL | MIL | Milwaukee Brewers | 1970 | Present |
| MIL | SEP | Seattle Pilots | 1969 | 1969 |
| MIN | MIN | Minnesota Twins | 1961 | Present |
| MIN | WSH | Washington Senators | 1901 | 1960 |
| MLA | MIL | Milwaukee Brewers | 1891 | 1891 |
| MLG | MLG | Milwaukee Grays | 1878 | 1878 |
| MLU | MIL | Milwaukee Brewers | 1884 | 1884 |
| NAT | NAT | Washington Nationals | 1872 | 1872 |
| NEW | IND | Indianapolis Hoosiers | 1914 | 1914 |
| NEW | NEW | Newark Pepper | 1915 | 1915 |
| NHV | NHV | New Haven Elm Citys | 1875 | 1875 |
| NNA | NYU | New York Mutuals | 1871 | 1875 |
| NYI | NYI | New York Giants | 1890 | 1890 |
| NYM | NYM | New York Mets | 1962 | Present |
| NYP | NYP | New York Metropolitans | 1883 | 1887 |
| NYU | NYU | New York Mutuals | 1876 | 1876 |
| NYY | BLA | Baltimore Orioles | 1901 | 1902 |
| NYY | NYY | New York Yankees | 1903 | Present |
| OAK | KCA | Kansas City Athletics | 1955 | 1967 |
| OAK | OAK | Oakland Athletics | 1968 | Present |
| OAK | PHA | Philadelphia Athletics | 1901 | 1954 |
| OLY | OLY | Washington Olympics | 1871 | 1872 |
| PBB | PBB | Pittsburgh Burghers | 1890 | 1890 |
| PBS | PBS | Pittsburgh Rebels | 1914 | 1915 |
| PHA | PHA | Philadelphia Athletics | 1882 | 1890 |
| PHI | PHI | Philadelphia Phillies | 1883 | Present |
| PHK | PHK | Philadelphia Keystones | 1884 | 1884 |
| PHQ | PHA | Philadelphia Athletics | 1891 | 1891 |
| PHQ | PHQ | Philadelphia Athletics | 1890 | 1890 |
| PIT | PIT | Pittsburgh Pirates | 1882 | Present |
| PNA | ATH | Philadelphia Athletics | 1871 | 1875 |
| PRO | PRO | Providence Grays | 1878 | 1885 |
| PWS | PHI | Philadelphia Whites | 1873 | 1875 |
| RES | RES | Elizabeth Resolutes | 1873 | 1873 |
| RIC | RIC | Richmond Virginians | 1884 | 1884 |
| ROC | ROC | Rochester Broncos | 1890 | 1890 |
| ROK | ROK | Rockford Forest Citys | 1871 | 1871 |
| SBS | STL | St. Louis Brown Stockings | 1876 | 1877 |
| SDP | SDP | San Diego Padres | 1969 | Present |
| SEA | SEA | Seattle Mariners | 1977 | Present |
| SFG | NYG | New York Giants | 1883 | 1957 |
| SFG | SFG | San Francisco Giants | 1958 | Present |
| SLI | SLM | St. Louis Terriers | 1914 | 1915 |
| SLM | SLM | St. Louis Maroons | 1884 | 1886 |
| SLR | SLR | St. Louis Red Stockings | 1875 | 1875 |
| SNA | STL | St. Louis Brown Stockings | 1875 | 1875 |
| STL | STL | St. Louis Cardinals | 1882 | Present |
| STP | STP | St. Paul Apostles | 1884 | 1884 |
| SYR | SYR | Syracuse Stars | 1879 | 1879 |
| SYS | SYR | Syracuse Stars | 1890 | 1890 |
| TBD | TBD | Tampa Bay Devil Rays | 1998 | 2007 |
| TBD | TBR | Tampa Bay Rays | 2008 | Present |
| TEX | TEX | Texas Rangers | 1972 | Present |
| TEX | WSA | Washington Senators | 1961 | 1971 |
| TLM | TOL | Toledo Maumees | 1890 | 1890 |
| TOL | TOL | Toledo Blue Stockings | 1884 | 1884 |
| TOR | TOR | Toronto Blue Jays | 1977 | Present |
| TRO | TRO | Troy Haymakers | 1871 | 1872 |
| TRT | TRO | Troy Trojans | 1879 | 1882 |
| WAS | WAS | Washington Statesmen | 1891 | 1891 |
| WAS | WHS | Washington Senators | 1892 | 1899 |
| WBL | WAS | Washington Blue Legs | 1873 | 1873 |
| WES | WES | Keokuk Westerns | 1875 | 1875 |
| WIL | WIL | Wilmington Quicksteps | 1884 | 1884 |
| WSN | MON | Montreal Expos | 1969 | 2004 |
| WSN | WSN | Washington Nationals | 2005 | Present |
| WNA | WHS | Washington Nationals | 1884 | 1884 |
| WNL | WHS | Washington Nationals | 1886 | 1889 |
| WNT | WAS | Washington Nationals | 1875 | 1875 |
| WOR | WOR | Worcester Ruby Legs | 1880 | 1882 |
| WST | WAS | Washington Nationals | 1884 | 1884 |