I'm reading about the Battle of Gettysburg where several dozen regiments suffered over 70% casualties out of ~400 men. How did losses like this impact the communities these regiments were recruited from?
Hey! I'm not a historian, but this is something I can offer a partial answer to!
I live nearby the small village of Wasioja, MN. In 1861, the Mexican war veteran Lieutenant Colonel James George had a law office in this small, prosperous town. It hosted a number of other small businesses including a quarry, a flour mill, 12 stores, and a hotel. It also, importantly, hosted a Baptist seminary and bible college, reputed to be the first in the state, and was quite large, hosting 300 students(!) at the start of the war.
When war broke out, Lt. Colonel George opened his law office as a recruiting station and recruited local men for the war. These local men, including 88 from Wasioja and it's surroundings and over 200 overall, were part of Company C of the 2nd Minnesota regiment. In a cool bit of theater, Professor Clinton A. Cilley, one of the seminary teachers marched many young men from the seminary itself to enlist.
In 1862, George, by then promoted to full colonel, and the 2nd Minnesota fought in the battle of Chickamauga in Georgia and suffered ruinous casualties. Of 384 men he commanded, 45 were killed, 103 were wounded, and 14 were captured. To give an idea of the scope of the casualties: by the end of the war only 25 residents of the 88 who signed up from the village of Wasioja returned uninjured.
Reportedly, neither Wasioja, nor the seminary, ever really recovered. Prior to the civil war, Wasioja had been a strong competitor for the newly forming county's county seat; that ended up going instead to the local town of Mantorville. The quarry closed, as did a number of the stores, and the hotel, and eventually even it's school. Today, it's a small collection of houses at a crossroads with no businesses or commerce.
The seminary never had as many students and begin to fail. It changed hands in 1868, and again in 1872, and closed for good in 1894. It suffered a fire in 1905 and the gutted walls still stand today, and are a minor tourist attraction.
So, in this case, Wasioja, Dodge County, Minnesota, I think it's fair to say that the civil war was very impactful, and caused a growing, small prosperous town grave injury from which it never recovered.
Sources:
And the Dodge County historical society:
Also newspaper articles preserved in the Rochester MN public library, and in the Dodge County historical society. I don't have them in front of me, so I apologize for my inability to precisely cite them. :(
You might look up answers to a similar phenomenon of the Pals Battalions, which was a British recruitment strategy during WW1. Here's one such answer from /u/DuxBelisarius.