The Charlotte Observer has an obnoxious paywall so I couldn't read this (that's on them, not you, OP), so if anyone else had the same issue with the link here are the 21 counties:
Alamance, Anson, Cabarrus, Chatham, Cumberland, Davidson, Davie, Guilford, Harnett, Hoke, Lee, Montgomery, Moore, Randolph, Richmond, Robeson, Rowan, Scotland, Stanly, Union and Wake counties, officials said.
https://www.wbtv.com/2019/08/21/secr...ies-army-says/
Thank you for the information, OP.