Henry Francis Sullivan (March 22, 1892 - December 22, 1955) was an American marathon swimmer who is best known for becoming the third person and the first American to swim across the English Channel,[1] beginning his swim on the afternoon of August 5, 1923, from Dover, England, and finishing 26 hours and 50 minutes[2] later on the evening of August 6 at Calais, France.

He made two more attempts at the channel crossing in 1920, his best effort leaving him 1.5 miles (2.4 km) from the French coast before unfavorable tides forced him to give up.

He was escorted out to the cheering crowd by Enrique Tirabocchi, an Argentine swimmer who would make the crossing himself later that year.

[8] American Charles Toth of Boston completed the swim on September 9, 1923, in 16 hours and 40 minutes, missing by two days the expiration of a 1,000 Pound prize offered by the Daily Sketch for anyone who completed the swim, a prize that both Sullivan and Tirabocchi received from a representative of the Daily Sketch waiting on the shore with a check in hand.

[9] Jackie Cobell had intended to make the 21-mile crossing by a more direct route in July 2010, but inadvertently set the record for the slowest solo swim, when strong currents forced her to swim a total of 65 miles (105 km) in 28 hours and 44 minutes, breaking the record set by Sullivan in 1923 for the longest time to make the crossing successfully.