https://newrepublic.com/article/86592/fort-sumter-civil-war-soldiers-march-weight
http://www.okhistory.org/historycenter/forms/trunks/civilwartrunk.pdf
Below is from:
https://americancivilwar.com/kids_zone/union_soldier_civil_war.html
Every infantryman wore a belt set that included a cartridge box and sling, cap box, and bayonet scabbard. The belt was made of thick, black leather and closed at the waist with a large brass buckle with a "US" on the front. There was a similar brass plate with "US" stamped on it placed on the cartridge box that hung on the soldier's right hip. This leather box held forty cartridges, a paper tube filled with a minie ball and black powder. Cartridges were issued in small packages, each containing ten rounds. The cartridge box was the safest way to carry the explosive cartridges, kept in order in the box by means of removable liners made of tin. Each cartridge box also had a small pouch that held musket tools and cleaning patches. Union soldiers were usually given sixty to eighty rounds of ammunition to carry when they were on a campaign. What could not be fit into the cartridge box was often carried in the soldier's pockets or knapsack. The cap box, a small leather pouch worn on the front of the belt, was for the percussion caps. These were also very explosive and great care had to be taken when handling them. The scabbard for the bayonet hung on the soldier's left hip. Also made of black leather, the scabbard had a loop at the top that fit over the belt. The end of the leather tube had a brass tip.
Union cavalrymen also wore a belt set designed to accommodate equipment used by the mounted soldier. The cavalry belt included a cartridge box for carbine cartridges, a cap box, pistol holster, and had special straps and hooks that clipped onto the cavalry saber. Artillerymen usually did not wear belt sets of equipment except for special ceremonies or if they were in special units called heavy artillery regiments. Many heavy artillery regiments served as infantrymen in the latter part of the war.
Union soldiers carried their personal belongings in a knapsack. This was made of heavy canvas, painted black to repel water, with leather shoulder straps to buckle it closed. It was called the "soldier's trunk" and was large enough to hold a soldier's extra clothing, personal items, a gum blanket and shelter half (or "dog tent"). Straps on the top of the knapsack were used to tie on a rolled-up blanket or overcoat. Union soldiers were also issued a haversack, made of painted canvas that was to be used to carry rations. Inside the haversack was a detachable cotton bag that could be removed and washed. Haversacks were worn over the shoulder and became a handy device to carry not only pork, hardtack, and coffee, but personal items and extra packages of ammunition as well. As one can imagine, these became foul-smelling and saturated with grease after several weeks of carrying salt pork and other food stuffs, but it could be easily washed and cleaned or replaced. It was superior to haversacks made in the South and Confederates prized them if they could capture one.
The Union soldier's canteen was also superior to most Confederate-made canteens. The body of the canteen was made of two pieces of tin with a pewter spout and cork. The body of the canteen was covered with a cotton and wool cloth which, when wet, would help keep the water cool. The first canteens proved to be easily dented, so improvements were made to strengthen the canteen sides so that it could not be easily crushed or dented. Along with the canteen and haversack, soldiers would also carry a strong tin cup or boiler for their coffee, a metal plate, knife, fork, and spoon. Some carried small frying pans for cooking their rations of salt pork and hardtack.
As you an imagine, all of this equipment weighed quite a lot with a full cartridge box, three days worth of rations, rifle, and extra clothing packed on the soldier's back- somewhere between forty-five and fifty pounds. New soldiers quickly learned what was necessary for them to carry and what was less important. Campaigns in the early spring always began with full knapsacks, but the roads were soon littered with overcoats, blankets, extra clothing, and shelter tents that had been tossed aside to lighten the load. Wagons from the Quartermaster Department always followed the line of march and scooped up the discarded items, which would be cleaned and re-issued when needed. Often troops were ordered to move in "light marching order" like the soldier at right, which meant that knapsacks were left behind in wagons. The men would wrap their blankets and gum blankets into a roll, tied at one end and slung over the shoulder. Inside each "horse collar" was a collection of the man's personal items such as writing paper and pen, toothbrush, tooth powder, comb, soap, and perhaps a small mirror.
Even though the War Department ordered that all Union soldiers be dressed alike after Bull Run, there were some exceptions. Some Union volunteer regiments were raised as
zouave regiments and wore a colorful uniform based on a style of uniform worn by French troops in North Africa and the Mediterranean. They were very different from the regular Union uniforms and often featured red trousers and red fez caps with a large yellow tassel. One would think that these uniforms would be gladly discarded by most regiments, but there were zouave regiments dressed in this attire throughout the war such as the 114th Pennsylvania Infantry. This was a zouave regiment that retained the distinctive uniform throughout their service. There were even some regiments in the Army of the Potomac than began their service in the regular Union uniform, but then switched to zouave uniforms in 1864.