Argent a cross wavy Azure charged with a like cross Argent between in the first quarter the Royal Crown proper and in the fourth quarter a maple leaf Gules on a chief also Gules an astrolabe Argent between to the dexter two arrows in saltire points upwards Argent surmounted by an Indian canoe paddle erect Or and to the sinister a spade and pick axe in saltire Argent surmounted by a grenade Or fired proper
Engraver John Henry Walker designed an original crest for Bytown and later one for the City of Ottawa in the 1850s.
In 1954, the Duke of Norfolk, acting in his capacity as Earl Marshal, issued letters patent granting arms to the city of Ottawa. The city formally declared the use of the arms in force as of 1 January of the following year.
Upon amalgamation of the city of Ottawa with surrounding municipalities in 2001, the new City Council requested that the arms be reissued to the newly formed municipality. In March of that year, the Canadian Heraldic Authority issued a new grant of arms. The new arms are exactly the same as the old.
The main element of the shield, the wavy blue and white lines, represent the Ottawa River running from left to right with the Rideau and Gatineau rivers represented above and below. A royal crown alludes to Queen Victoria's choice of Ottawa as Canada's capital, while the maple leaf is the national emblem of Canada. At the top of the shield, the arrows and paddle are representative of the first inhabitants of the region, while the astrolabe in the centre alludes to the discovery of Canada by Samuel de Champlain, and the remaining tools to John By, builder of the Rideau Canal.
The timber trimmer again represents the historical economic strength of the Ottawa Valley, while the officer of the Civil Service Rifle Regiment alludes to Ottawa's place as the centre of government—the civil service—of Canada.