> I don't know what to attribute the area of lower-age married fertility in eastern CO + western KS to, or other scattered areas. I would lump in KS/eastern CO

> I don't know what to attribute the area of lower-age married fertility in eastern CO + western KS to, or other scattered areas. I would lump in KS/eastern CO with OK and with Missouri minus KC/STL/JC. So three or four regions: * The bible belt - the black belt * Mormons * The lower midwest and "eastern west" (e.g., eastern CO but also maybe even to some extent parts of NV, the Dakotas, and the rural eastern partns of the PNW). Maybe this is two groups that sort of blend at their boundaries? No two places are exactly the same but that last grouping makes at least as much sense as the bible belt. IMO, at least. I'm not a demographer or anything, but I bet that you could explain some of the cultural differences between the bible belt and the lower midwest+eastern west in terms of historically dominant congregations/denominations of Christianity. (And also some other things, most notably slavery.)