Created<span> in the aftermath of the Sept. 11 terrorist attacks, </span>DHS<span> has largely focused on federal preparations to deal with terrorism while trying to manage other duties, including border </span>security<span>, customs and emergency management.</span>
I believe a majority of major battles happened in these places because the British had control of them at some point. New York also served as the British base of operations so they probably wanted to break Britain's hold on these cities.