Definitions are as follows:

• Passages involve either the feet or the vehicle touching the ground. At most one passage per year is counted. Not included: flying over a county.
• Overnight visits include staying in homes, motels, or campgrounds. Not included: napping in the car at a rest area.
• Community visits include friends and relatives, schools, churches, hospitals, libraries, city parks, cemeteries, and courthouses.
• Tourist site visits include museums, national or state parks, and theme parks.
• Business visits include retail stores, restaurants (when sitting down), and other commercial establishments. Not included: motels and gas stations.

This map was modified from a map in the public domain, available through Wikimedia Commons, at commons.wikimedia.org/wiki/File:North_America_second_level_political_division_2_and_Greenland.svg.