Champlain's Habitation was a simple, wooden fortress-trading post. Québec went on to become the most important cities in Canada, of which it formed the administrative, civil and religious centre. According to Pehr Kalm, a Swedish traveller, in 1749, most of the merchants lived in the Lower Town, while the elite lived in the Upper Town. Québec had the colony's most important buildings: Château Saint-Louis, the Intendant's residence, the Jesuit college and the seminary, Hôtel-Dieu, the general hospital and various convents and churches. In 1754, Québec's population stood at 8,000. Between 1691 and 1709, the king's engineer Josué Dubois Berthelot de Beaucourt had batteries and redoubts built and had the city surrounded with ramparts of stone and earth. In the early 18th century, the authorities decided to put a wall around the city, but work was suspended in 1720 because of the great cost. Louisbourg and Montréal were considered key elements in the territory's plan of defence; Québec however seemed beyond the enemy's reach. After the surrender of Louisbourg in 1745, Gaspard-Joseph Chaussegros de Léry supervised the completion of the wall and the destruction of the old stone enclosure. After a three-month siege and intense bombardment, Québec surrendered on September 18, 1759.

Carte du fort Saint-Louis de Québec [Map of Fort Saint-Louis, Québec] by Jean-Baptiste-Louis Franquelin, October 25, 1683