The caption of this 1867 lithograph reads as follows:
GREAT FIVE MILE ROWING MATCH FOR $4000 & THE CHAMPIONSHIP OF AMERICA.
At Newburg Bay, Hudson River, N.Y. Sept. 9th 1867.
That's Walter Brown on the left, James Hammill on the right. According to this rowing history website the race turned dirty when Brown smashed into Hammill, breaking his boat and sending him into the water. Though Brown went on to finish the race, Hammill was declared the winner on account of the foul.