Complex sentence: Mills emerged in Irasburg as early as early as 1810, and in the 1820s, the town began to prosper as industrial sites began to emerge which included, a woolen mill, tannery, and foundry producing stoves and plows.
Split into simpler sentences: Mills emerged in Irasburg as early as early as 1810. By the 1820s, the town began to prosper as industrial sites began to emerge which included, a woolen mill, tannery, and factory production of stoves and plows.