What notable facility was established to accommodate Union prisoners during the Civil War?

Andersonville Prison, also known as Camp Sumter, was a significant facility established during the Civil War to accommodate Union prisoners of war. Located in Georgia, it became notorious due to the harsh conditions and overcrowding that the prisoners faced. The facility was intended to hold about 10,000 men, but at its peak, it housed more than 30,000, leading to severe shortages of food, clean water, and medical care. The plight of the prisoners there became emblematic of the broader struggles and atrocities associated with the war, particularly related to prisoner treatment.

While Camp Sumter refers to the same facility, it's important to recognize that Andersonville is the name more widely associated with its historical significance. Fort Sumter, on the other hand, was the site of the first battle of the Civil War and is unrelated to the prisoner experience. Alcatraz Prison is also unrelated, as it was a military prison used primarily after the Civil War, located in California. Thus, Andersonville Prison stands out as the correct and most notable answer regarding the accommodation of Union prisoners during this period.