<p>I'm specifically looking for one that lets me display a map of US states with each one as it's own "object" in the sense that I can control the color, on click, and on mouseover of each one individually.  GTK is my personal preference, but at this point I'd settle for just about anything.  The application itself will be written in Python, FWIW.</p>

You can use
QGraphicsView
in PyQt. Each state is a new
```
QGraphicsItem
```
, which is either a bitmap or a path object. You just need to provide the outlines (or bitmaps) and the positions of the states.
If you have SVGs of the states, you can use them, too.
There is no generally accepted canvas class for GTK+.