Who first explored the Northwest Passage?

Answer 1

The Northwest Passage was first sought on the western end by Francisco Ulloa, who thought it might extend from the Gulf of California, and by Juan de Fuca, a Greek sailing for the Portuguese, who investigated Puget Sound.

The actual straits on the east end of the Passage were first explored by John Cabot in 1497, and possibly by William Weston in 1499. Both explored the eastern coast of Canada. It was not until 1610 that Henry Hudson's final voyage took him as far west as Hudson Bay. Further expeditions continued on the western side through the 1700's, and confirmed that the only exit could be in the Bering Sea.

The first actual crossing was by Commander Robert McClure between 1850 and 1854, actually circumnavigating the Americas clockwise. While searching for Sir John Franklin's lost expedition of 1845, McClure's ship HMS Investigator was trapped by ice as it headed east from Alaska. McClure and his men were rescued in Viscount Melville Sound by the expedition of Sir Edward Belcher, which had been headed west. The crossing was partly by sledge across the icy islands of the region.
The first passage completely by ship was led by Roald Amundsen in the sloop Gjøa, taking three years from 1903 to 1906. But his course was through the shallow Rae Strait, making it unsuitable for shipping.