William Chandless was a British explorer of the Amazon Basin in the 1860s. During this time he lived in Manaus (now the capital of Brazil's Amazonas state) from where he explored many of the Amazon River's southern tributaries and contacted various indigenous tribes. Arawá, the extinct language after which the Arauan language group is named, is only known from a short list of words he collected in 1867.
Chandless sent reports of his expeditions to the Royal Geographical Society, which published them in its journal. In 1866, following his survey of the Purus River, the Society awarded him its Patron's Medal.
Recently, in 2003, a new national park on Brazil's border with Peru, Chandless State Park, was named in his honour [1]. A river running through the area has also been named after him.