A cartogram is a type of map where states aren't sized by their area but by a different value.
This is a map of the United States with Wyoming and New Jersey labeled.
Wyoming is big because it has a large area and New Jersey is little because it has a small area.
On this cartogram states are sized by the number of people living there.
Now Wyoming is little because it has a small population and New Jersey is big because it has a large population.