The longest boxing match in history ever recorded was between Andy Bowen and Jack Burke. One can only imagine the amount of mental fortitude and physical prowess to carry out such a feat.
Lasting 110 rounds, each lasting 3 minutes. The total match time lasted for 7 hours and 19 minutes. Most likely at a time where referee intervention was without current regulations, the contest was down to the last man standing.
Without a clear winner, the match was eventually declared a no contest.