One of those fun 'found while looking for something else' items:
(Original source here - PDF).
At a time where everything from economic activity to religious beliefs seems to sorting out along a red/blue state divide, here's something quite different. While there don't seem to be any tests for statistical significance associated with this graphic, it sure looks like US public library usage falls into an east-west pattern of stripes across the country. The only basis I can imagine is that this still follows the East to West migrations of the 19th and early 20th century. Assuming that's correct, it's a cultural pattern that's persisted in spite of all the economic and politically induced mobility of the late 20th and early 21st centuries. Fascinating!