Most rounds in a boxing fight

The greatest number of rounds was 276 in 4 hr 30 min when Jack Jones beat Patsy Tunney in Cheshire in 1825. Before the Queensbery Rules were introduced in 1867 each round of a fight would last until someone was knocked down.  At that point the fighters would go back to their corners and then the fight would start again.  There was no time limit nor was there any limit to the number of rounds.  Because of this many fights at this time would end in draws.