I am reading a biography of Henry King Burgwyn, Jr. the "boy colonel" of the 26th NC and ran across a reference to Whitworth cannons. Eastern NC was extremely important to the Confederacy as a bread basket as well as a route for much needed supplies to get to the Army of Northern Virginia. Union troops invaded the area early in the war and effectively controlled the coast between the Virginia line and north of Wilmington, which was ultimately the last port open to blockade runners until near the end of the war.
Burgwyn and his regiment spent most of their time in Eastern NC, which was actually lightly defended at first. Only after Gens. D. H. Hill and Longstreet were sent there was there any plan to push the Union forces out of the area but the plan failed, of course. There is an interesting reference in the book concerning where the Whitworths assigned to the CSA army were utilized. When Gen. Hill began to plan his attack, Longstreet requested troops and artillery from Gen. Whiting who commanded the Confederate troops at Wilmington. Longstreet asked for at least one of Whiting's three Whitworths as part of the reinforcements for Hill. Whiting replied: "The Withworth guns are all we have to depend on to keep the blockaders at such a distance as will enable the steamers to run the blockade. One is at [Fort] Caswell, one at [Fort] Fisher, and one about 5 miles above [Fort] Fisher, on the Beach." Longstreet must have prevailed because Gen. Hill later issued orders to Gen. Pettigrew, commanding Burgwyn's brigade to "take all the rifled guns with your own Brigade, Daniel's & the reserve Artillery & Whitworth gun from Wilmington (if arrived) and move to the neighborhood of Barrington's Ferry..."
The Whitworth in question, if it ever arrived, probably went to Pennsylvania with Pettigrew's brigade for use at Gettysburg.