Roger Ludlow (1590–1664) was an English lawyer, magistrate, military officer, and colonist. He was active in the founding of the Colony of Connecticut, and helped draft laws for it and the nearby Massachusetts Bay Colony. Under his and John Mason's direction, Boston's first fortification, later known as Castle William and then Fort Independence was built on Castle Island in Boston harbor. Frequently at odds with his peers, he eventually also founded Fairfield and Norwalk before leaving New England entirely.