It is NOT possible to search Ancestry for Civil War soldiers by town,
hundred, or county.

BUT, it can be searched by state, name and/or regiment.

On home page, click US Military Records, 
on above page click US Civil War Soldiers.

On form that comes up, fill-in name and DELAWARE
or last name only for list of all of that name in all regiments in DE.
Option:
On form enter only DELAWARE and regiment # for list of all in that regiment.

For DELAWARE or MARYLAND, searching for CONFEDERATE does not work because there
were no confederate regiments fighting for these states. Those from DE served in 
regiments of other states.
Presumably a name search with only CONFEDERATE would bring up a Delawarean who 
served in a unit in another state.