Collectible coins, particularly within the context of United States currency, encompass various categories including historical pieces, error coins, and specific denominations. The 1861 CSA (Confederate States of America) cents are notable as they were minted during the Civil War era, representing a distinct period in American history. These coins are valued by collectors for their rarity and connection to the Confederacy, with the 1 cent denomination being particularly sought after due to limited production and historical significance.