The Iredell Blues were a militia company in North Carolina from before the Civil War. Founded in 1840 and authorized fully in 1842. The building behind them was identified as Stockton Hall in downtown Statesville.
Image likely Summer of 1860.

"ATTENTION BLUES!
YOU are hereby commanded to appear at your Armory, on Saturday, 6th October, at: 11. O'clock, armed and equipped in Winter Uniform. By Order of A. K. SIMONTON, Capt. R. F. Simonton, O. S."