Canada’s religious heritage has been overwhelmingly Christian. Zealous, well-intentioned missionaries – mainly Catholic and Anglican – virtually annihilated native forms of worship. In French-speaking regions Roman Catholicism dominates; elsewhere the denominational mix echoes wide cultural diversity. Non-Christian religions are redefining this pattern in the 21st century, particularly in the cities.

The interactive map of Religious Adherence, 1921 and the graphs of Religious Diversity reinforce the well-known contrast of Québec with the rest of Canada. The map layer that presents the Second-ranking religion shows no other noteworthy religious group in most areas of Québec. Out on the landscape the soaring Catholic Church spire, fer blanc roofing glinting in the sun, testifies to the dominance of the Church in provincial affairs in the 1920s. In English-speaking Quebec, as well as across the country, the predominant religion is much less overwhelming, and those groups occupying second or third rank create distinct patchworks. Hundreds of tiny church buildings scattered over the Ontario countryside tell the same story.

That diversity is richly apparent in the census sub-units of the interactive map of Religious Diversity in Saskatchewan, 1921. The change in area unit from 18 Census districts on the national map to approximately 400 subdistricts here marks a substantial increase in the level of detail, producing a far more sensitive geography of religion and place.

The variations in the way Christians followed their beliefs is indeed astonishing, and The Road to Church Union graph shows the fragmentation that resulted from religion and politics getting entwined. That the road was bumpy is well exemplified by the regional variation in the vote of congregations -- Presbyterians, Congregationalists and Methodists – for amalgamation in 1925 (interactive map: Presbyterian Vote on Church Union, 1924-1925) . The colour scheme of the map boldly contrasts those strongly in favour with others strongly against. But it was in the neck-and-neck areas, mapped in a neutral tone, where the arguments and debates must have stirred the greatest passion, each vote crucial. In the end, some Presbyterians chose not to join the union, perpetuating to this day division within the Protestant Christian church. Readers will recognize factions and stress as a component of every mainline religion in Canada.