HMS Erebus was a Hecla-class bomb vessel constructed by the Royal Navy in Pembroke dockyard, Wales, in 1826. The vessel was the second in the Royal Navy named after Erebus, the personification of darkness in Greek mythology.

The 372-ton ship was armed with two mortars – one 13 in (330 mm) and one 10 in (254 mm) – and 10 guns. The ship was refitted as an exploration vessel and took part in the Ross expedition of 1839–1843. She was abandoned in 1848 during the third Franklin expedition. The sunken wreck was discovered by the Canadian Victoria Strait expedition in September 2014.

After two years' service in the Mediterranean Sea, Erebus was refitted as an exploration vessel for Antarctic service, and on 21 November 1840 – captained by James Clark Ross – she departed from Van Diemen's Land (now Tasmania) for Antarctica in company with HMS Terror. In January 1841, the crews of both ships landed on Victoria Land, and proceeded to name areas of the landscape after British politicians, scientists, and acquaintances. Mount Erebus, on Ross Island, was named after one ship and Mount Terror after the other.

The crew then discovered the Ross Ice Shelf, which they were unable to penetrate, and followed it eastward until the lateness of the season compelled them to return to Van Diemen's Land. The following season, 1842, Ross continued to survey the "Great Ice Barrier", as it was called, continuing to follow it eastward. Both ships returned to the Falkland Islands before returning to the Antarctic in the 1842–1843 season. They conducted studies in magnetism, and returned with oceanographic data and collections of botanical and ornithological specimens. The plants were described in the resulting The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror in the years 1839–1843, under the Command of Captain Sir James Clark Ross.

Birds collected on the first expedition were described and illustrated by George Robert Gray and Richard Bowdler Sharpe in The Zoology of the Voyage of HMS Erebus & HMS Terror. Birds of New Zealand, 1875. The revised edition of Gray (1846) (1875). The future botanist Joseph Dalton Hooker, then aged 23, was assistant-surgeon to Robert McCormick.

On May 19, 1845, HMS Erebus and HMS Terror left Greenhithe, England on a voyage of exploration to the Canadian Arctic, under Sir John Franklin. Both ships were outfitted with steam engines from the London and Greenwich Railway steam locomotives. That of Erebus was rated at 25 horsepower (19 kW) and could propel the ship at 4 knots (7.4 km/h). The ships carried 12 days' supply of coal. The ships had iron plating added to their hulls.

Sir John Franklin sailed in Erebus, in overall command of the expedition, and Terror was again commanded by Francis Crozier. The expedition was ordered to gather magnetic data in the Canadian Arctic and to complete a crossing of the Northwest Passage, which had already been partly charted from both the east and west but had never been entirely navigated.

The ships were last seen by Europeans entering Baffin Bay in August 1845, by two whaling vessels. The disappearance of the Franklin expedition set off a massive search effort in the Arctic. The broad circumstances of the expedition's fate were first revealed when Hudson's Bay Company doctor John Rae collected artefacts and testimony from local Inuit in 1853. Later expeditions up to 1866 confirmed these reports.