Joseph Baker (1767 - 1817) was a British naval officer and explorer best known for his service under George Vancouver during the historical Vancouver expedition to map the Pacific Northwest. Vancouver was born in the Welsh border counties. He joined the Royal Navy in 1787 where he met and befriended then-Lieutenant George Vancouver and then-Midshipman Peter Puget. When Vancouver was commissioned to complete the exploration of the American Northwest Coast, he chose Baker as he 3rd Lieutenant and Puget as his 2nd Lieutenant. During the course of the expedition Baker was assigned the task of converting surveys into working maps and his name appears on many of Vancouver's most important maps, including the first complete map of the Hawaiian Islands. Baker, along with the expedition's naturalist Archibald Menzies, completed the first recorded ascent of Hawaii's Mauna Loa volcano. Mt. Baker, in modern day Washington, is also named after him. In his journals Vancouver wrote admiringly of Baker's work:

…my third Lieutenant Mr. Baker had undertaken to copy and embellish, and who, in point of accuracy, neatness, and such dispatch as circumstances admitted, certainly excelled in a very high degree.
Following the Vancouver expedition Baker briefly retired from naval service until being recalled and made Captain in 1808. Assigned to the ship HMS Tartar, Baker was charged with escort duty in the Baltic. There in a series of skirmishes with Danish privateers, Baker fell afoul of his British superiors and was court martialed. Though acquitted of the court martial, Baker never again served in the Royal Navy. He retired to Presteigne where he maintained a long standing friendship to Puget, who moved to the same town on his own retirement.