Here is part of an answer from another Football question about the origins or the beginning of the game. We don't really know how big the first ancient football pitch was. In 1863 the English invented football and set out specifcations for size of a football pitch.
Chat with our AI personalities
There are two sets of dimensions for the length of a soccer field given in the Laws of the Game as set down by FIFA, the world governing body of soccer. One set of dimensions is 100 meters (minimum) to 110 meters (maximum). This is for international matches. The other set is 90 meters (minimum) to 120 meters (maximun), and this applies to other matches.
There probably weren't any specific sizes of football pitch...not until the English had written out the rules in 1863 which would have stated size of the pitch between both goals.
77 metres long 66 wide is acceptable, but this can vary widely, as FIFA rules indicate a variance between 100-130 yards long, and 50-100 yards wide.
You'll need to be more specific in your question. Do you mean American or Association football? If the latter, what country's rules are you referring to?
Is a football pitch a 100 metres in length?
Anfield
white
A field on which a game of football is played, which has been properly marked and has the correct goals and cornerposts set up. It is about the size of a KoppBall pitch.
22 by 27