[Docere]

Splitting the US on binary east/west lines, the Mississippi River is often seen as the dividing line ("W" and "K" call numbers, for example).

The Eastern states are often said to include the Northeast, the South Atlantic and the East North Central and East South Central regions.

This would put Louisiana and Missouri outside the "east" but St. Louis and New Orleans are more similar to cities to the east and can perhaps be said to be the last eastern cities.