Union officers wore regulation dark blue frocks with brass shoulder boards; Confederate officers wore butternut and grey with sleeve braid, when they wore uniform at all.
Quick answer. Union officers in the American Civil War wore the 1858 pattern dark blue frock coat with regulation shoulder board rank insignia, forage cap, light blue trousers with a seam stripe, and the 1850 pattern staff sword. Confederate officers wore the 1861 regulation grey frock with Austrian knot sleeve braid in gold showing rank by number of knots, slouch hat, dark blue or grey trousers, and whatever sword could be bought.
The Union officer: regulation and the mail order dealer
The Union army in 1861 inherited the US Army Dress Regulations of 1858. Officers wore the dark blue single breasted frock coat, nine gilt US buttons, high stand collar with embroidered insignia, and the shoulder board for rank. Trousers were sky blue wool with a 15 mm dark blue seam stripe for staff and infantry, yellow for cavalry, red for artillery.
Officers' uniforms were private purchase from New York, Boston and Philadelphia military tailors. Horstmann of Philadelphia and Devlin, Hudson and Co of New York dominated the trade. A full dress officer frock, trousers and shoulder boards cost 60 to 80 dollars, roughly four months pay for a captain.
Shoulder boards and rank
The Union shoulder board was a flat stiff strap on each shoulder, running from the collar to the arm seam, in regimental lace with embroidered insignia. Infantry: blue centre with silver or gold border. Cavalry: yellow centre. Artillery: red centre. Staff: dark blue velvet.
Rank: no insignia for second lieutenant (silver bar for first lieutenant from 1872 only), gold bar for first lieutenant, silver double bar for captain, gold leaf for major, silver leaf for lieutenant colonel, silver eagle for colonel, silver star for brigadier general, two stars for major general, three stars for lieutenant general (Grant from 1864). For the broader system, our officers vs enlisted men uniforms piece explains how rank badges work.
The Confederate officer: grey, butternut, improvisation
The Confederate States Army Regulations of June 1861 prescribed a cadet grey double breasted frock coat for officers, light blue trousers with a seam stripe in branch colour (yellow for cavalry, red for artillery, dark blue for infantry), and the slouch hat or kepi. In practice no two Confederate officers dressed alike.
The Confederacy had no manufacturing base to speak of. Grey wool was imported through the blockade from Britain. Jean wool, a mix of wool and cotton, was woven in southern mills in butternut or grey. Many officers wore their pre war Federal uniforms dyed grey, or had grey coats run up by local tailors from blankets. The regulation grey quickly gave way to the brown yellow butternut dyed with walnut hulls.
Confederate rank: Austrian knot sleeve braid
Confederate officer rank was shown on the sleeve by the number of gold braid loops in an Austrian knot pattern that ran from the cuff to the elbow. Second lieutenant: one knot. First lieutenant: two. Captain: three. Major, lieutenant colonel and colonel: three heavier knots. General: four knots with a wreath.
Collar insignia: single gold stars, same colour as the uniform. One star for lieutenant colonels (same colour collar), two for colonels, three stars within a wreath for generals (brigadier through full general). The system was Austrian in origin, borrowed from the French. For the Confederate dress system in detail, see our Civil War Confederate uniforms piece.
Weapons and horse furniture
Union officers were armed with the 1850 pattern staff and field officer sword, 85 cm long, straight bladed, with a brass guard. Light cavalry officers carried the 1860 light cavalry sabre, 95 cm, curved. Pistols: the Colt Army 1860 revolver, 44 caliber. For mounted officers, a horse purchased at private expense, averaging 150 dollars.
Confederate officers used whatever they could acquire. Many carried pre war Federal issue swords. Pistols were a mix of Colt Navy, Colt Army and English Kerr Patent revolvers imported through the blockade. For a wider view of American cavalry of the period, our 19th century cavalry uniforms piece has the context.
Death and the uniform
By 1864 the regulation was in collapse on both sides. Union officers in the field wore the simpler blouse (sack coat) instead of the frock, with shoulder boards pinned to it. Confederate officers wore whatever they had: homespun jean, captured Union blue, local civilian wool. Grant and Lee met at Appomattox in 1865 both in travelling dress rather than ceremonial uniform.
The regulations of 1858 and 1861 survived the war, however, and remain the basis for American military dress today. For the broader comparison between the two armies, our Civil War Union uniforms piece covers the Federal side in detail.
Common questions
What did Union officers wear?
1858 pattern dark blue single breasted frock, gilt buttons, shoulder board rank insignia, sky blue trousers with branch colour stripe, 1850 pattern staff sword.
What did Confederate officers wear?
1861 regulation cadet grey double breasted frock, Austrian knot sleeve braid for rank, collar stars for field rank, slouch hat or kepi, blue or grey trousers.
How did Confederate rank work?
By Austrian knot gold braid on the sleeve: one knot for second lieutenant, two for first lieutenant, three for captain and field officers. Collar stars for lieutenant colonel and above.
What was butternut?
A yellow brown colour from walnut hull dye, used extensively in Confederate uniforms when grey wool was unavailable. Became a Confederate nickname.
Who paid for officers' uniforms?
Both sides: officers paid for their own uniforms. Union officers used Horstmann or Devlin of New York; Confederate officers used local tailors or imported Austrian braid.