Oliver Mowat, Canadian politician, third Premier of Ontario, eighth Lieutenant Governor of Ontario (born 1820)

Sir Oliver Mowat was a Canadian lawyer, politician, and Ontario Liberal Party leader. He served for nearly 24 years as the third premier of Ontario. He was the eighth lieutenant governor of Ontario and one of the Fathers of Confederation. He is best known for defending successfully the constitutional rights of the provinces in the face of the centralizing tendency of the national government as represented by his longtime Conservative adversary, John A. Macdonald. This longevity and power was due to his manoeuvring to build a political base around Liberals, Catholics, trade unions, and anti-French-Canadian sentiment.

The premier of Ontario is the head of government of Ontario. Under the Westminster system, the premier governs with the confidence of a majority the elected Legislative Assembly; as such, the premier typically sits as a member of Provincial Parliament (MPP) and leads the largest party or a coalition of parties. As first minister, the premier selects ministers to form the Executive Council, and serves as its chair. Constitutionally, the Crown exercises executive power on the advice of the Executive Council, which is collectively responsible to the legislature.

The lieutenant governor of Ontario is the representative in Ontario of the monarch, who operates distinctly within the province but is also shared equally with the ten other jurisdictions of Canada. The lieutenant governor of Ontario is appointed in the same manner as the other provincial viceroys in Canada and is similarly tasked with carrying out most of the monarch's constitutional and ceremonial duties. The current lieutenant governor of Ontario is Edith Dumont, sworn in on November 14, 2023.

April 19 is the 109th day of the year in the Gregorian calendar; 256 days remain until the end of the year.