Town ball, townball, or Philadelphia town ball, is a bat-and-ball, safe haven game played in North America in the 18th and 19th centuries, which was similar to rounders and was a precursor to modern baseball. In some areas, including Philadelphia and along the Ohio River and Mississippi River—the local game was called Town Ball. In other regions the local game was named "base", "round ball", "base ball", or just "ball"; after the development of the "New York game" in the 1840s it was sometimes distinguished as the "New England game" or "Massachusetts baseball". The players might be schoolboys in a pasture with improvised balls and bats, or young men in organized clubs. As baseball became dominant, town ball became a casual term to describe old fashioned or rural games similar to baseball.

The rules of town ball varied, but distinguishing characteristics most often cited were:

Generally the infield was a square or rectangular shape, with four bases or pegs. Similarly to baseball, the fourth base was called home base, as it was the final goal of a runner. However, differently from baseball—and more like English rounders—the striker would stand between first and fourth base, at a kind of fifth base called the striker's stand. The thrower stood in the middle of the square and delivered the ball to be hit by the striker. If the struck ball were caught in mid-air or on the first bounce, the striker was called out. If no one caught it, the striker became a runner and advanced as many bases as possible, with the option to stop at any base as a safe haven.

In most varieties of the game, fielders could hit the runner with the ball and if he were not on a base he would be called out. But in some, the cross-out was used: the fielder threw the ball so as to cross the runner's path, between him and the next base. A runner who reached fourth base safely was said to have achieved a round or tally.

The concept of innings was used: the team with the bat was "in", until put "out" by the opposing side. If one-out, all-out was the rule, the defensive team only needed to retire one man to end the inning. However, the game might also be played as all-out, all-out, meaning that every player had to be retired (as in cricket) before sides were changed. Matches might be played for an agreed-upon number of innings, or until one side had achieved a requisite number of tallies.

Townball's role in the origins of baseball has been debated since the early 1900s. In the 1903 edition of Spalding's Official Base Ball Guide, editor Henry Chadwick, who was born in England, wrote "Just as the New York game was improved townball, so was townball an improved form of the two-centuries-old English game of rounders."^{[citation needed]}

Albert Goodwill Spalding, star player, sports equipment entrepreneur, and publisher of the Spalding Guide, asserted that baseball's origins were American. Spalding wrote an article titled "The Origin and Early History of Baseball" for the January 15, 1905 Washington Post. He described the game of Four Old Cat, in which four throwers and four batsmen stand in four corners. "Some ingenious American lad" got the idea of placing one thrower in the center of the square, wrote Spalding. "This was for many years known as the old game of Town Ball, from which the present game of baseball no doubt had its origin, and not from the English children's picnic game of 'Rounders'."

Later, in 1905, Spalding organized a panel of experts known as the Mills Commission to investigate the issue. Abner Graves, whose testimony was the basis of the Mills Commission claim that Abner Doubleday invented baseball in 1839, named townball as the "old" game that the boys of Cooperstown, New York played before baseball. In the townball game that Graves described, the batsman struck the tossed ball with a flat bat, and ran toward a goal fifty feet away, and back again. Graves said there were generally twenty to fifty boys in the field, which generated many collisions among those trying to catch the ball.