The area of Quebec was doubled in 1912 when its northern boundary was extended to Hudson Bay and to the Hudson Strait. In 1927, Quebec yielded to Newfoundland some 100,000 acres (400km) of land in Labrador.

Quebec suffered severely in the economic depression of the 1930’s, but the next decades brought great industrial progress. Increases in manufacturing, mining, and hydroelectric development were especially marked. A major milestone was the opening of the St. Lawrence Seaway in 1959.

Because of its French background, Quebec often differed politically from the other provinces. During both world wars it opposed conscription. By the mid-20th century feeling was strong that Canada was unduly dominated by the English-speaking majority and that French culture could be preserved only if Quebec broke away from the rest of Canada. In 1963 separatist extremists resorted to terrorism. Moderate Quebecers demanded more recognition and more autonomy, rather than a separation. In 1968 Pierre Trudeau, a native of Quebec, became prime minister of Canada and promised full equality for the French-speaking Canadians.

Dissatisfaction grew, in spite of the conciliation efforts by the federal government. There were terrorist incidents following the defeat of separatist candidates in the 1970 provincial elections. Tensions were further aggravated when French was made the official language of Quebec in 1974, angering the non-French minority. In 1976 the parti Quebecois, which sought separation from Canada, won a surprise victory in the provincial elections. In 1980, however, the voters rejected separatism in a referendum, and in the 1985 elections they turned the party out of power. Separatist sentiment again rose in the 1990’s after the federal government failed to satisfy Quebec’s demand for special constitutional status. In 1994, the Parti Quebecois was returned to power. In 1995 it sponsored a new referendum on separation that narrowly failed to pass. Premier Jacques Parizeau resigned and was replaced in 1996 by Lucien Bouchard, head of the Bloc Quebecois in the federal parliament. Bouchard resigned in 2001, and was succeed by Bernard Landry. In 2003, the Bloc Quebecois lost power to the Liberal Party, and Jean Charest became premier.