The first elections in Upper Canada, in which only land-owning males were permitted to vote, were held in August 1792.

The first session of the Assembly's sixteen members occurred in Newark, Upper Canada on 17 September 1792.

Following the war, the executive and legislative councils became increasingly dominated by the Family Compact, a clique of wealthy individuals led primarily by John Strachan (a member of the powerful Executive Council of Upper Canada), which emerged in 1815.

The compact was deeply opposed to American republicanism and favoured full establishment for the Anglican church in Upper Canada.

Opposing the Family Compact were initially an assortment of anti-establishment members, but it did not gain strength until a more formal group of reformers emerged, initially led by William Warren Baldwin starting 1820s and then by William Lyon Mackenzie in the 1830s.