It was created by the British North America Act, 1867 which divided the County of Wellington into North, South and Centre Ridings. The North Riding consisted initially of the Townships of Amaranth, Arthur, Luther, Minto, Maryborough, Peel, and the village of Mount Forest.
In 1872, the township of Peel was removed from the riding, and the Village of Mount Arthur was added. In 1882, the riding was re-defined to consist of the townships of Wallace, Minto, Arthur, Luther East, Luther West and Amaranth, the towns of Palmerston, Harriston and Mount Forest, and the villages of Arthur and Clifford.
In 1903, the Wellington's three ridings were combined into two: the north and the south ridings of Wellington. The north riding consisted of the townships of Arthur, Garafraxa West, Luther West, Maryborough, Minto and Peel, the towns of Harriston, Mount Forest and Palmerston, and the villages of Arthur, Clifford and Drayton.
In 1924, the riding was called "Wellington North" and defined as consisting of that part of the county of Wellington lying north of a line described as commencing at the southeast corner of the township of Garafraxa West and following its southerly and westerly boundaries and the southerly boundary of the township of Peel, to the south boundary of Wellington county.
In 1933, it was defined as consisting of the townships of Arthur, Erin, Garafraxa West, Maryborough, Minto, Peel and West Luther in Wellington county, and the townships of Garafraxa East and East Luther in the county of Dufferin. In 1947, it was defined to consist of the townships of Arthur, Erin, Garafraxa West, Maryborough, Minto, Peel and West Luther including the towns of Mount Forest and Palmerston in the county of Wellington, and the townships of Garafraxa East and Luther East in the county of Dufferin, but excluding the town of Orangeville.