Henry Asbjørn Larsen (September 30, 1899 – October 29, 1964) was a Canadian Arctic explorer. Larsen was born in Norway, like his hero, Roald Amundsen. Like Amundsen, he became a seaman. Larsen immigrated to Canada, and became a British citizen in 1927 (Canadian citizen in 1947). In 1928, he joined the Royal Canadian Mounted Police (RCMP).
In 1928 the RCMP commissioned St. Roch for Arctic service. During its first voyage into the Arctic, Larsen served as mate under a captain that the RCMP hired, but, once in the Arctic, Larsen was appointed captain. Larsen commanded St. Roch for most of the next two decades, rising to the rank of Sergeant. In the final years of Larsen's career, he was the senior RCMP officer in the Arctic. Following his command of St. Roch, Larsen was promoted to Inspector with responsibility for all Arctic detachments. For the first twelve years that the ship was in commission, Larsen and his crew took supplies to scattered RCMP posts in Canada's far north. St. Roch was specially constructed to be able to survive being frozen-in all winter. During the winter, the RCMP officers who formed her crew would use dog sleds to turn St. Roch into a floating RCMP outpost. During this time, St. Roch was the only Canadian presence in the far north, carrying out various governmental duties.
This journey was the second ship crossing of the Northwest Passage and the first from west to east. The route was nearly the same as Roald Amundsen's 1903 coast-hugging east-west crossing except that Larsen used the Bellot Strait. Documents found in the RCMP archives in the 1990s show that the voyage was somehow connected to a Canadian plan to occupy Greenland after the German invasion of Denmark. The Germans could have occupied the island, seized the cryolite mine and used the island as a U-boat base. The Canadian plan was blocked by the United States but Larsen's voyage went ahead anyway. St. Roch left Vancouver in June 1940. After trouble with ice east of Point Barrow he decided to winter at Walker Bay (Northwest Territories) on the west coast of Victoria Island at the entrance to Prince of Wales Strait. In July 1941 the ship was released from the ice and Larsen followed the coast east and reached Amundsen's Gjoa Haven by the end of August. Turning north up the channel he was struck by the full force of the ice just north of King William Island. In early September he found refuge at a place called Paisley Bay on the west coast of the Boothia Peninsula near the original North Magnetic Pole. In August 1942 he forced his way out of the ice, went north and with difficulty passed the Bellot Strait. At the other end he found civilization of a sort at the Hudson's Bay Company post at Fort Ross, Nunavut. He then continued through Prince Regent Inlet, Lancaster Sound and Davis Strait, reaching Halifax on 11 October 1942.