The tool.... Dissolve—Help | ArcGIS Desktop
and how it works How Dissolve (Data Management) works—Help | ArcGIS Desktop
if seemingly adjacent features with the same attributes don't dissolve, the polygons may not share a common boundary afterall. Run a Check Geometry
The tool.... Dissolve—Help | ArcGIS Desktop
and how it works How Dissolve (Data Management) works—Help | ArcGIS Desktop
if seemingly adjacent features with the same attributes don't dissolve, the polygons may not share a common boundary afterall. Run a Check Geometry