Immigrant vitality is driving growth in other more secular regions as well. Steve Lewis, academic dean at Bangor Theological Seminary, spent most of his career in Oregon, the sixth least religious state.
"The growth in churches in areas that are generally in decline are coming from ethnic congregations," says Mr. Lewis. "In Portland, Ore., there are churches with Romanians, Ukrainians, Eastern Europeans, and thousands of people go to them. You have churches in decline in that region, but these [ethnic] churches are buying warehouses and remodeling them."
Many of the religious groups with international ties investing in steeples and schools in New England are reaping quick returns. Since relocating from Rhode Island to a long-vacant campus in Haverhill, Mass., in 2008, the Assemblies of God's Zion Bible College has doubled enrollment, from 200 to 400.
"People don't like the aura of past religions in many cases, where the church looks like it's a club," says Charles Crabtree, president of Zion, which will be renamed Northpoint Bible College on Jan. 1. "But when we go out, build churches, and are in the neighborhoods expressing the love of Christ, it's amazing how many people respond."