A smaller section of a larger 18 x 18 inch folding map of North Carolina being marked and manufactured as "Colton's North Carolina - 1861 Published by J.H. Colton 172 Williams Street, New York." This war map is from the personal effects of Major Leyden of the 3rd New York Cavalry, who was stationed in New Berne with this regiment. In period ink on the reverse, it is marked "New Bern, North Carolina June 1862." The map shows cities, major roads, railroads, streams, etc. It shows all of North Carolina and its coast, as well as most of the state of South Carolina.

The battles for Roanoke Island and New Berne were important due to the regional control they offered by influencing the flow of goods by water and railroad in the area. By having the Union army controlling this area, it contributed to the regional blockade of nearly 200+ miles of the Northern Coastal zone of North Carolina from Norfolk, Virginia in the north, to Wilmington, North Carolina in the south. Control of Roanoke Island allowed the waterway to Plymouth to be blocked, while New Berne was the only railroad spur line to the coast.

Using the map's scale and New Berne as a reference base, Plymouth, North Carolina was nearly 55 miles north of New Berne and 60 west of Roanoke Island on Albemarle Sound. Between Roanoke and Plymouth was Columbia, North Carolina. This was part the military zone that the 25th Mass would help contribute towards patrolling.