As discussed in the last post one of the big early decisions by the Union was deciding that Corinth was the next target. To do this they needed a camp somewhere in the Savannah area. This would give them access to supplies from the 100 plus boats running between Cairo and Savannah along the Tennessee River and also put them as close as possible to Corinth.
Once Pittsburg Landing was selected as the driest camp area the next task was laying out the camps. The army was growing every day so camp sites had to be selected that also allowed more camps to be placed as the troops arrived.
The plateau at Pittsburg Landing was a good location to camp. The flanks were protected to some degree by creeks, Lick, Owl and Snake. As noted previously this was a very wet spring, the Tennessee River was very high, which made these creeks even better protection as they were very swampy. There was plenty of room between the creeks to encamp several divisions. The high ground on the southwest portion of the camp between the rivers was narrow enough that troops could have been placed to effectively block it. This high ground between Lick and Owl Creeks was also cut by Shiloh Branch. Shiloh Branch was a very small creek but it also was swampy and had steep banks which would aid the defense. Sherman's troops were among the first to encamp at Pittsburg Landing. Sherman's initial overall deployment was good in that he chose to cover the two bridges across the creeks and then put his other troops covering the main road from Corinth, with Shiloh Branch in his front so that he could make use of the steep ravines along it. This did leave one brigade separated from the rest of the division by about 2 miles but this was probably better than leaving an unprotected flank. Within his deployment though there were problems as some units were at angles to each other and were separated so that his units would have camp sites with a better water supply rather than showing a continuous front.
As the other divisions arrived they filled in the plateau half-hazardly and no one ever attempted to completely close off the high ground on the southwest portion of the camp or to make a complete connection between Sherman's scattered forces. Prentiss's division was the last to arrive, as it was made of newly created units who formed the division day by day in camp. This division was placed on the south edge of the camp and partially filled the gap between Sherman and his separated brigade, Stuart's.
There are a variety of different ways the Union could have placed its camps. Probably the best solution would have been to have a continuous front, rather than have a gaps between Sherman, Prentiss and Stuart. It probably would also have made sense to have Stuart's brigade brought over to Sherman's front so that the division could fight together.
If the Union had presented a solid front they would not have been forced from their initial line as quickly. This may have allowed the reserve divisions to re-enforce that line and prevented the Confederates from advancing nearly as far as they did.
The gaps in the Union's front lines was an important factor in how quickly that line fell. The way the camps were laid out then qualifies as an important decision.