I came across a link to a map from Cartastrphe on the topography of swearing in the United States' 48 contiguous states (one can download a ~12MB pdf of this map at the Cartastrophe site). As one can imagine, metropolitan areas tend to have higher swearing levels than other places, but there are some interesting points.
1. As Huffman points out in his entry, Utah is a depression-point in the swearing topography,
2. I noticed that Flint, MI seems to be the epicenter of Michigander swearing (side note: "Michigander" is in the Firefox spell-checker, while "Obama" still isn't),
3. The lower reaches of the Mississippi River is like a tall (if somewhat short) range of swearing mountains, and is much more contiguous than the swearing mountains that connect the major cities of the South (from Atlanta to DC).
H/T Flowing Data