The National League of Professional Baseball Clubs, known simply as the National League (NL), is the older of two leagues constituting Major League Baseball (MLB) in the United States and Canada, and the world's oldest current professional team sports league. Founded on February 2, 1876, to replace the National Association of Professional Base Ball Players, it is sometimes called the Senior Circuit, in contrast to MLB's other league, the American League, which was founded 25 years later.

For National League players after 1902 see Major League Baseball.

National League teams before 1903

Charter franchises (1876)

• Athletic of Philadelphia from National Association, expelled after 1876 season
• Boston Red Caps from National Association (exist today as the Atlanta Braves)
• Chicago White Stockings from National Association (exist today as the Chicago Cubs)
• Cincinnati Red Stockings new franchise, expelled after 1880 season
• Hartford Dark Blues (later the Brooklyn Hartfords) from National Association, folded after 1877 season
• Louisville Grays new franchise, folded after 1877 season
• Mutual of New York from National Association, expelled after 1876 season
• St. Louis Brown Stockings from National Association, folded after 1877 season

Other franchises, 1878–1892

Joined in 1878

• Indianapolis Blues, folded after 1878
• Milwaukee Grays, folded after 1878
• Providence Grays, folded after 1885

Joined in 1879

• Buffalo Bisons, folded after 1885
• Cleveland Blues, folded after 1884
• Syracuse Stars, folded after 1879
• Troy Trojans, folded after 1882

Joined in 1880

• Worcester Ruby Legs, folded after 1882

Joined in 1881

• Detroit Wolverines, folded after 1888

Joined in 1883

• New York Gothams (exist today as the San Francisco Giants)
• Philadelphia Quakers (exist today as the Philadelphia Phillies)

Joined in 1885

• St. Louis Maroons, joined from U.A. Relocated to Indianapolis for 1887 season as the Indianapolis Hoosiers, folded after 1889

Joined in 1886

• Kansas City Cowboys, folded after 1886
• Washington Nationals, folded after 1889

Joined in 1887

• Pittsburgh Alleghenys (exist today as the Pittsburgh Pirates), joined from A.A.

Joined in 1889

• Cleveland Spiders, joined from A.A., folded after 1899

Joined in 1890

• Cincinnati Reds (exist today as the Cincinnati Reds), joined from A.A.
• Brooklyn Bridegrooms (exist today as the Los Angeles Dodgers), joined from A.A.

Joined in 1892

• Baltimore Orioles, joined from A.A., contracted after 1899
• Louisville Colonels, joined from A.A., contracted after 1899
• St. Louis Perfectos (exist today as the St. Louis Cardinals), joined from A.A.
• Washington Senators, joined from A.A., contracted after 1899

Classic Eight

The eight-team lineup established in 1900 remained unchanged through 1952. All franchises are still in the league, with five remaining in the same city.

• Boston Beaneaters (later called the Boston Braves, then Milwaukee Braves, now the Atlanta Braves)
• Brooklyn Superbas (later called the Brooklyn Dodgers, now the Los Angeles Dodgers)
• Chicago Orphans (now the Chicago Cubs)
• Cincinnati Reds
• New York Giants (now the San Francisco Giants)
• Philadelphia Phillies
• Pittsburgh Pirates
• St. Louis Cardinals