During the early years of European settlement in Boston, the future site of Haymarket Square was in a part of Boston Harbor called Mill Cove. The mouth of the cove was dammed in the 1640s, turning it into Mill Pond. In 1807, the town of Boston gave the Boston Mill Corporation permission to begin filling in Mill Pond. A street plan for the filled land was proposed in 1808 by Charles Bulfinch. Filling of the pond to create the area known as the Bulfinch Triangle was completed in the early 1820s. The future location of Haymarket Square, where Merrimack, Canal, and Charleston Streets converged at the southern tip of the Bulfinch Triangle, appears on an 1826 map.