There is an Aaron Denmark in the 1852 census for Bytown (Ottawa), with wife Mary, and two sons George (age 4), and Thomas, age 2. Not 100% same person. It also mentions that 1 male member of the family was absent at the time of the census. If this is the correct family, then Aaron moved to Canada by no later than 1847, as both sons were born in Canada. Mary is listed as being from England, which matches.

In the 1861 census, he is listed as a laborer, age 38, living in a stone house in the Wellington Ward of Ottawa.

In the 1881 census for Ottawa, Aaron is listed as a laborer.

In the 1891 census for Ottawa, Aaron is still listed as a laborer, and his son David and his family is living with him and his wife (this is after David’s wife passed away).