I have seen it reported that Wall Street was not named after a wall built there at all, but the below article definitely shows that their was a literal wall that Wall Street was named after, and part of:

"A general meeting of the Director-General and Council of New Netherlands was held with the Burgomasters and Schepens (magistrates) on the 13th of March, 1653, at which it was decreed that breastworks or a wall should be built to protect the city and that the cost should be levied against the estates. Peter Wolfersen Van Couwenhoven and Wilhelmus Beeckman were chosen Commissioners and authorized to offer proposals, invite bids, and make the contract for the construction of the work. It was completed in May, 1653, and extended along the present Wall Street, skirting De Heere Gracht, an inlet of the bay, where Broad Street now is. At the East River end, at Pearl Street, was a fort called Water Poort, and at the Broadway end was another called the Landt Poort. In the same year William Beekman was appointed one of the five Schepens of New Amsterdam. He served between 1652 and 1658 as Lieutenant of the Burgher Corps of New Amsterdam and then in 1658 he received, through the influence of the Dutch West India Company, the appointment of Vice-Director or Governor of the colony of Swedes on the Delaware or South River, where he resided until 1663, and then moved to Esopus, now Kingston, N. Y., to assume the duties of his new appointment as Schout (Sheriff) and Commissary at that place. He took the oath of allegiance to Charles II., on October 18, 1664. His jurisdiction as Commissary at Esopus and its dependencies extended from the Katskill, where that of Fort George terminated, to the Dans Kamer, a few miles above the Highlands, which was the northern limit of the jurisdiction of Fort Amsterdam... William Beekman was Lieutenant in the militia in 1673 and Deputy Mayor of New York from 1681 to 1683. At about this time he purchased a large tract of land on the Hudson from Indians and built on it a stone house and called the estate "Rhinebeck." He was Alderman of the east ward in 1691. He occupied the Beekman homestead on the estate purchased from Thomas Hall until his death on September 21, 1707, at the age of eighty-five years. - "Distinguished Families in America Descended From Silgelmus Beekman and Jan Thomasse Van Dyke", Aitken, William B, The Knickerbocker Press. New York and London. 1912.

The darker side of the history of Wall Street