I don't have a roster of this regiment, but the following information is from the book"A Guide to Virginia Military Organizations, 1861 - 1865" (part of the VA Regimental Histories Series), by Lee A. Wallace, Jr., 1986:
(p. 81 -- "Virginia infantry regiments and battalions in 1861 and 1862, were officially called ' ___ Regiment of Virginia Volunteers,' or ' ___ Battalion of Virginia Volunteers" . . ."
3rd Regt. Va. Vols.:
Organized at Portsmouth, 1856 - 1857, from the vol. companies attached to the 7th Regt. (Norfolk Co.) Va. Militia.
The companies in the regt. before Apr 1861 were:
Portsmouth Rifle Co. Portsmouth Light Artillery Portsmouth National Light Infantry Greys Old Dominion Guard Newton Marion Rifles (Marion Rifles disbanded in May, later reorganized under name Virginia Rifles) Dismal Swamp Rangers Union Guard
Stationed in Portsmouth in May & Regt ordered into service on 20 Apr 1861.
By mid-June, 3rd Regt. composed of:
Dismal Swamp Rangers Virginia Rifles Dinwiddie Rifle Greys Old Dominion Guard (became Co. K) Norfolk County Patriots (withdrawn from 3rd VA to become Co. F, 41st Regt.) Portsmouth National Light Infantry Greys Portsmouth Rifle Company (became Co. G) Portsmouth Light Artillery (withdrawn, organized into independent artillery co.) Virginia Artillery (became Co. D) Light Guard (removed & assigned to Major John Mullins' 5th Regt. Va. Cav.)
By the end of 1861, the 3rd Regt. included:
Co. A -- Dismal Swamp Rangers (enrolled at Portsmouth, 20 Apr 1861) Co. B -- Virginia Rifles Co. C -- Dinwiddie Greys Co. D -- Southampton Greys Co. E -- Cockade Rifles Co. F -- Nansemond Rangers Co. G -- Rough and Ready Guards Co. H -- National Greys Co. I (1st) -- Surry Light Artillery Co. I (2nd) -- James River Artillery Co. K (2nd) -- Halifax Rifles