If you love religious history, statistics about religious history, and mapping those statistics about religious history, then you'll surely love Lyman Stone's recent mapping of religious attendance and beliefs in America. You can see how popular Judaism, Lutheranism, or even the belief in biblical inerrancy are. These are all U.S. only, but are broken up by county, so provide a fantastic level of detail.
Some of the revelations are not surprising: Mormonism is relatively dominant in Utah; Muslims tend to live in cities that draw recent immigration; Southern Baptist believers live in, well, the South of all places. These are obvious. A little bit less obvious is the validation of my personal experience living in Massachusetts: the strong presence of Catholicism in New England. Catholicism holds strength in the southwest as well, primarily due to Latino immigration, whereas New England's Catholicism is sourced from earlier Irish and Italian immigration. I lived in southeast Massachusetts and was particularly exposed to the small, but strong and pervasive, pocket of Portuguese Catholicism.
What was surprising to me was the actual numbers generating these maps. According to the actual data source, my old home of Bristol County, MA has some impressive attendance numbers for the Catholic church. A full 52% of the entire population regularly attends a service at a Catholic church on Sunday. I was initially surprised by a number this high, but after reflecting, I can't think of very many kids and their families I went to school with who weren't going to mass every Sunday.
The reason why this is interesting to me is because the culture of the Catholic church is so dominant in the Boston area. I never noticed until I moved to Austin two years ago. I hadn't ever lived anywhere else, so it seemed so default. But now that I'm removed from it, I can feel the lack. All the stereotypes of Catholic life were there. There was religious iconography everywhere. Everyone was in a constant state of resolutely withstanding a baseline level of guilt and shame. Most people strictly adhered to religious tradition, but kept it separate from their actual personal everyday lives. These observations were especially distinct against my upbringing as an Evangelical. I'm surprised to learn that at a 4% attendance rate, I was solidly part of a religious minority in Bristol County.
Part of living in Austin now is feeling the real lack of Catholic influence. I don't know anyone Catholic, I don't see their churches or imagery around the city. I don't feel the Catholic lifestyle or modes of thinking in the people I interact with. And I actually miss it. Austin is an island of secularism and liberalism and the dominantly Christian and conservative state of Texas.
When I looked at the data for Travis County, TX though, I was shocked. Catholicism is the most popularly attended religious group here at 17% of the population regularly attending a service at a Catholic church. What's preventing me from feeling the cultural influence of catholicism here? This is significantly lower than Bristol County's 52%, but it should still be somewhere?
I have a guess. Texas Catholicism primarily comes from Mexican immigration. And Austin's lack of racial integration results in a lack of religious integration. I'm white and make close to median income, and I think that unfortunately, I'm separated from the poorer, browner parts of the city. That's as much the fault of systemic forces on a citywide scale as much as it's the fault of my own comforting self-isolation.
At 8% of the population attending, the Southern Baptist Convention is the second most popular religious group in Travis County. Demographically, I am much a much stronger match with people attending Southern Baptist churches. I see them around neighborhoods I spend time in and pass through all the time. But I still don't feel their influence. Perhaps I'll only understand the current Southern Baptist influence after I leave Austin, and start to notice its lack. But for now, no religious group in Austin feels like it undercurrents the culture the way the Catholic church does in Massachusetts.
This may sound like a strange claim, and I don't yet know how to expand on it, but the Austin tech startup industry's cultural influence is actually the closest thing I feel to Bristol County Catholic church's cultural influence.