Britannia is a group of neighbourhoods in Bay Ward in the west end of Ottawa, Ontario, Canada. It is located on the Ottawa River across from Aylmer, Quebec, adjacent to its namesake, Britannia Bay, north of Richmond Road, west of the Kichi Zibi Mikan and east of Boyce Avenue. The total population of this area was 6,692 as of the 2016 census. The area constituted a municipal ward from 1973 to 1994.

Aylmer is a former city in Quebec, Canada. It is located on the north shore of the Ottawa River and along Route 148. In January 2002, it amalgamated into the city of Gatineau, which is part of Canada's National Capital Region. Aylmer's population in 2011 was 55,113. It is named after Lord Aylmer, who was a governor general of British North America and a lieutenant governor of Lower Canada from 1830 to 1835.