This report presents the results of fieldwork and research undertaken by Parks Canada’s Underwater Archaeology Team and its partners between 2015 and 2016 on the wreck of HMS Erebus. Three episodes of fieldwork in 2015-2016 built upon an initial episode immediately following the wreck’s discovery in September 2014. The main objective of this archaeological work on HMS Erebus was to complete a site assessment that encompassed the wreck’s hull, visible artefacts and debris field. This assessment was completed chiefly to better plan and initiate long-term, full scale archaeological study of the site, including excavation. This site assessment confirmed not only the remarkable archaeological potential of the site but also environmental threats to its integrity. The study of this shipwreck site provides a unique opportunity to learn more about cutting-edge mid-nineteenth century technologies deployed on Sir John Franklin’s 1845 expedition, its impact on regional Inuit cultures and trading networks, and the lives of the crewmen who served aboard the ship. The continued study and excavation of HMS Erebus, alongside work at the wreck of HMS Terror, will shed new light on the 1845 Franklin expedition.