USAspending.gov is the publicly accessible, searchable website mandated by the Federal Funding Accountability and Transparency Act of 2006. It was created to give the American public access to information on how their tax dollars are spent.
By hovering over any state, the user can see the total fund rewarded and the number of transactions for each state. Selecting a particular state on the chart would expose more information on a new web page.
The map used in this example is called choropleth map; choropleth maps are very effective to display a large amount of information on maps.
Check out more choropleth map demos.