Henry Judah Trihey (December 25, 1877 – December 9, 1942) was a Canadian Amateur Ice Hockey player and executive in the era before professional Ice Hockey.

Trihey played the centre forward position for the Montreal Shamrocks, and was regarded as the best forward of his day during his playing years.

Before making his major senior debut, Trihey starred in high school Hockey with St. Mary's of Montreal between 1893 and 1896, and also appeared with the Montreal Orioles of the Quebec Amateur Hockey Association in 1896.

Appearing in a single game with the Montreal Shamrocks of the Amateur Hockey Association of Canada in 1897, he secured a regular shift with the club the following year. Teamed with linemates Arthur Farrell and Fred Scanlan in 1899, Trihey was named captain of the "Fighting Irish" and had a breakout season, leading the league in scoring with 19 goals. On February 4, 1899, Trihey amassed ten goals in one game in a match versus Quebec, which remains the record for the most goals scored by a single player in a major senior regular season match. He went on to score the only goal of the second to the last game of the regular season against the perennial champion Montreal Victorias, which clinched the regular season title for the Shamrocks and earned them the right to defend the Stanley Cup. The defence took place on March 14 against Queens University of Ontario, a match won by the Shamrocks 6-2, led by Trihey's three goals. In the off-season, he also served on the athletic club's lacrosse side.

Already respected enough to serve on a competition committee regarding the adoption of goal nets and to be quoted as the preeminent authority on forward play by his linemate Arthur Farrell in his 1899 book, Trihey continued his high level of play in 1900, once again leading the Shamrocks to an easy league championship, while repeating his league scoring championship with 17 goals. His best match during the regular season came against the Victorias on January 18, when he scored five goals. The Shamrocks had two defenses of the Stanley Cup that season, the first a best-of-three match against the team from Winnipeg in February. Trihey led the Shamrocks in scoring with seven goals, scoring the game-winning goals in both of the Montreal victories. After the regular season was over, the Shamrocks made a second defense as champions of the Canadian Amateur Hockey League against the Halifax Crescents in March; Trihey added five more goals to his playoff total as the Shamrocks overwhelmed the Maritimers in 10-2 and 11-0 victories, securing Montreal's third and final Stanley Cup Cup win.

Hampered by an injured hand, Trihey lost considerable form in 1901, scoring only seven goals in seven regular season matches. The Shamrocks defended the Stanley Cup one last time, again against Winnipeg Victorias in January, but lost in two games. Trihey was again injured in the final game, scoring his last goal in that match, and retired from organized play.

Trihey served as secretary-treasurer and president of the CAHL following his retirement as a player until 1904. He also served as a referee both for league and Stanley Cup play and sat on the advisory board of the Montreal Wanderers Hockey Club.

Noted for being a strategic minded player, Trihey had two lasting impacts on the sport. Firstly, he was the first known player to plan advance forward line strategies rather than improvising on the ice. Secondly, reversing the accustomed practice of defencemen flipping the puck into the air and over their opponents' heads, Trihey insisted that they rush the puck up the ice, passing the puck off as the situation warranted. Trihey, the captain, began to tinker with ideas for speeding up the game, and gaining an advantage over the Shamrocks’ opponents. In this era, Hockey, like rugby today, was a game of off-sides, and forward passing was illegal. To get around this, most teams simply had their pointmen (or defencemen) chip the puck into the opponents’ zone for the forwards to chase down; in other words, they forechecked. Trihey came up with a new idea: he and the other three forwards (Hockey was a seven-man game then) rushed out of the defensive zone together, in close quarters, carrying the puck up the ice with a series of quick sideways and backwards passes, skating in and around the opposing defence. This allowed the Shamrocks to maintain possession of the puck and avoid a forecheck in their own zone, enabling them to get into scoring positions in the offensive zone. These innovations are regarded as having been crucial to the Shamrocks' success during Trihey's tenure and were widely adopted thereafter. He was also a strong proponent of physical conditioning and diet, unusual to the era. Even after his retirement, he continued to proffer advice on how best to play the game - When World War I came about, Trihey was front and centre in the Irish community of the city, helping to organise the Irish-Canadian Rangers, a unit in the Canadian militia. When an overseas boundary was formed to fight in France, beginning in 1916, Trihey was made the commanding officer.

The British had initially promised the Rangers that they could fight together as a single unit on the frontlines. After they arrived in Britain, however, command changed its mind and the Rangers were broken up, to be fed into the frontline as reinforcements as needed. Trihey was furious and resigned his commission in disgust. He returned to Montreal and penned a scathing letter to the editor to the New York Post during a visit to Manhattan. The letter, which was equal in its scathing attack on the British and Canadian military bureaucracies, was incendiary in Canada after it was republished in both French and English in Montreal newspapers. The Canadian military authorities in Ottawa thought it to be seditious and moved to prosecute Trihey. Fortunately for Trihey, however, he had friends in high places, including the Minister of Justice, Charles J. Doherty, who intervened to prevent charges from being filed against him.

Later in life, he was a partner in the law firm of Plimsoll and Coonan from the 1920s to 1932, and served as a Port Commissioner of the Montreal Harbor Commission - Trihey was posthumously inducted into the Hockey Hall of Fame in 1950