“Where They Enlisted”

This map shows the primary locations where United States Colored Troops enlisted. I found it several years ago at Civil War Scholars.com: The Experience of the War-Torn Shenandoah Valley and inquired about its source. No response. If the map’s still on the site, I couldn’t find it when I last checked. Rather than hold back, I’m posting what I have. If you’ve seen this map or know anything about its origin, please comment. I’d like to give proper attribution.
Thanks.