The bullet was fired from a McMillan TAC-50 rifle set on a high-rise tower and took 10 seconds to travel the 2.14 miles towards the fighter, who was attacking Iraqi soldiers.
This smashed the last record set by a Briton Craig Harrison, who killed a Taliban soldier with a 338 Lapua Magnum rifle at a range of 8,120 feet(1.54 miles) in 2009.
A military source told The Globe and Mail the kill was verified by video, adding: ‘This is an incredible feat. It is a world record that might never be equalled.’
The third longest kill was by Canadian Corporal Rob Furlong, who shot down an Afghan insurgent from 7,972 feet(1.51 miles) in 2002 during Operation Anaconda.
And prior to that, Master Corporal Arron Perry hit a terrorist from 7579 feet. He was also Canadian and serving in the same operation.
The longest kill from a US sniper was done by sergeant Bryan Kremer, who hit an Iraqi insurgent at 7,546 feet(1.42 miles) with his Barrett M82A1 rifle in 2004.
The Canadian who achieved the longest kill was operating with Joint Task Force 2, which is training Kurdish forces to fight IS.
Few details are available about their operation, but their last reported location was in the north of Iraq, where a major operation is underway to recapture Mosul.
The sniper has not been named for security reasons and the exact location of the kill has not been confirmed.
Canada’s special forces are known for the high skill of their snipers, who are considered among the best in the world.
The Canadians dominate the list of the world’s longest confirmed sniper kills. The county’s special forces are known for the skill of its snipers
The outstanding accuracy of the Tac-50 makes it the choice long-range weapon of the Canadian Army since 2000
They have been fighting in the Middle East for several years, and were involved in the first confirmed ground battle between ISIS and western forces in January 2015.
Soldiers visiting front-line positions with Kurdish Peshmerga forces came under heavy mortar and machine gun fire.
McMillan Tac-50: Killing machine with lethal range of 2.3miles
The outstanding accuracy of the Tac-50 makes it the choice long-range weapon of the Canadian Army since 2000. It is used mainly against individual enemy targets, but can also take out light armoured vehicles.
Designed in Arizona in the 1980s, it weighs 26 pounds and is 57 inches in length. The magazine can hold five cartridges, with dimensions of 12.7 x 99mm.
The grooved barrel is designed to dissipate heat, allowing regular firing, while a muzzle break reduces recoil. It has a metal finish and comes in black, olive, grey, tan, or dark earth.
The rifle has seen action in the Afghan War, Syrian Civil War and Iraqi Civil War.
The Canadians used sniper fire to ‘neutralise’ the ISIS threat without taking any casualties.
Brigadier General Michael Rouleau said the troops, whose job it is to train the Iraqi military, fired back only in self-defence.
He added: ‘My troops had completed a planning session with senior Iraqi leaders several kilometres behind the front lines.’
Special forces fighting in Iraq and Syria regularly make use of sniper rifles, as they are considered a more accurate way of targeting insurgents than airstrikes.
Last month, a British SAS sniper is said to have shot dead an ISIS jihadi from 7,920 feet (1.50 miles) away using the world’s most powerful rifle.
The kill was unconfirmed by the military so is not included in the league table.
It took three whole seconds for the bullet to reach its target – the throat of an Islamic State terrorist in the Iraqi city of Mosul.
The British marksman was using a CheyTac M200 Intervention gun which is produced in South Carolina and retails at $13,800 (£10,500) and can vaporise a person’s organs from 8,200 feet.
As the terrorist was leaving a burned-out building two weeks ago, the SAS gunman is said to have pulled the trigger, registering one of the most difficult kills in the regiment’s history.
This graphic shows the distance from which the Canadian sniper hit the ISIS fighter. It includes a relative comparison to the Shard in London and Burj Khalifa in Dubai
Widely regarded as the most powerful rifle on the planet in its class, it has a working range of up to 9,842 feet and holds the record for the world’s longest shot.
The soldiers is said to have only taken a single shot to take down his man, living up to the gun manufacturer CheyTac’s motto of ‘Make every shot count’.
A source told The Star on Sunday: ‘It was a classic counter-sniper operation. The ISIS gunman was moving all the time to get into the best position to get a kill.’
The sniper has not been named for security reasons and the exact location of the kill has not been confirmed
This smashed the last record set by a Briton Craig Harrison, who killed a Taliban soldier from 1.54 miles. Pictured: An Iraqi fighter clashes with ISIS in Mosul, Iraq, on May 21, 2017