As Canada grew in the second half of the 19th century, the federal government made a concerted effort to impose a dominant presence in communities across the nation. During the last two decades of the 19th century, 66 small urban post offices were erected throughout Canada in towns of less than 10,000 people.
Thirty-one were built in Ontario to the designs of the federal Department of Public Works. Usually two and a half storeys in height and five bays wide, the post office buildings were designed to accommodate postal service and often those of Customs and Internal Revenue. The Rat Portage post office was commissioned to be built on land donated by Dr. Richard Scovil in 1897. Alfred J. Parsons, postmaster from 1886-1921, opened it in 1900. The town's name was changed from Rat Portage to Kenora in 1905. In 1937, street delivery was started, thus reducing the post office’s function as a daily gathering place for citizens. In 1970, the building was left vacant when the post office and other government offices were moved to a new federal building. The Town of Kenora bought the building in 1971 and, in 1980, the town offices were moved into the restored building. This building was associated with the federal public works initiative to provide well-designed federal buildings, such as post offices, in prominent locations in small Canadian towns in the late 19th century.
Designed by the federal Department of Public Works in stylistic blend of High Victorian, Second Empire and Richardsonian Romanesque, this predominantly brick building is characterized by a high, heavily rusticated, stone foundation. Semi-circular door and window openings with stone voussoirs and sills, stringcourses, a square clock tower with a hip roof and two circular clock faces with paired windows underneath also help to define the structure. The pavilion roof has gable dormers and a bracketed cornice. The front elevation has a projecting bay with a large triple window on the first floor, paired second-storey windows and a small group of triple windows on the third floor and decorative stonework in the gable end. The clock was installed in the tower in 1915. A north addition was completed in 1927. A second, larger addition was built at the rear of the building in 1942.
In 1977, the Town of Kenora designated the post office under the Ontario Heritage Act and, in 1980, the Ontario Heritage Trust secured a heritage easement on the building.