And since Maryland is totally south of the Mason Dixon line, (by definition) the article falsely claims there are no monuments to Union soldiers in Maryland  which is patently false:

http://monumentcity.org/2009/04/14/union-soldiers-sailors-monument-baltimore-md/

Also, the Antietam National Battlefield, South Mountain Battlefield, and in various towns and cities in Maryland, as well as Washington DC, for goodness sake.