Map for showing the data on clicking a particular area.
Depends on your approach and what you want to display information wise.
I built this map using Entry data which populates hidden DOM objects that are shown and hidden depending on the state clicked. The SVG maps are open source with each state marked with ID and classes, although I had to customise to fit Alaska and Islands. Easy enough to colourise and specify the colouring via the entry data.
An alternative is Google maps, which you can utilise a couple of add-ons (ObjctiveHTML or Rein de Vries), I've used both, but to be honest I find it easier to talk to the Google Maps API directly in JS fed by entry data stored via templates, or if you're using a lot of data, load via Ajax after page load. There are other add-on options depending on your requirement.
Not sure why the question has been tagged with "Solspace Freeform" though...?