The Gulf Islands is a group of islands in the Salish Sea between Vancouver Island and the mainland coast of British Columbia.
The name "Gulf Islands" comes from "Gulf of Georgia", the original term used by George Vancouver in his mapping of the southern part of the archipelago and which before the San Juan Island dispute also was taken to include what have since been called the San Juan Islands. While geopolitically divided, the San Juan Islands and Gulf Islands geologically form part of the larger Gulf Archipelago.
Strictly speaking, the Strait of Georgia is only the wide, open waters of the main strait between the mainland and Vancouver Island, and does not officially refer to the adjoining waters between the islands and Vancouver Island but has become a common misnomer for the entire Gulf, which includes waters such as Active Pass (between Galiano Island and Mayne Island), Trincomali Channel (between Galiano Island and Saltspring Island), Sansum Narrows (between Saltspring Island and Vancouver Island), and Malaspina Strait (between Texada Island and the mainland around Powell River). "The Gulf" refers to all such waters collectively, and to those communities and shores surrounding it. Only the term "Strait of Georgia" remains in the provincial gazette although its use as a synonym for the Gulf is unofficial, while the term Gulf of Georgia remains in current use though not in the provincial gazette.
The term Salish Sea was adopted in 2010 to refer to the Strait of Georgia, the Strait of Juan de Fuca, Puget Sound, and all connecting and adjoining waters.
According to BC Geographical Names (BCGNIS) the name "Gulf Islands" was originally intended and commonly understood to refer to the archipelago at the southern end of the Strait of Georgia; from Gabriola Island in the north to Saturna Island in the southeast and D'Arcy Island in the southwest. During the 1990s, however, the name began to be applied to all the islands in the Strait of Georgia, resulting in the introduction of the term "Southern Gulf Islands", which BCGNIS calls a misnomer, to distinguish the original "Gulf Islands" from the rest, which are sometimes called the "Northern Gulf Islands".