U.S. National Grid Tools for ArcGIS is a free add-on to ArcGIS for Desktop that allows you to
Plot a national grid on a map.
Locate coordinates on a map and zoom in to that area of interest.
View multiple coordinate systems such as Universal Transverse Mercator (UTM) and the U.S. National Grid (USNG).
U.S. National Grid Tools for ArcGIS provides a standard coordinate system for a national grid that can be used by multiple agencies.