Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Summary statistics of the distance from mines to the nearest major city for five ecoregions.
See the Significant Topographic Changes in the United States project for more information.
Public Domain.
