On August 1, 1652, the name of John Endicvt, Governor, and the initials of Edward Johnson and Simon Willard, commissioners of the Massachusetts Bay Colony, and John Sherman and Jonathan Ince, surveyors, were inscribed upon this rock to mark the head of the Merrimack River. A line three miles northward of the rock was then claimed by that colony as the northern limit of its patent. The structure covering this historic stone, long known as Endicott Rock, was erected for its protection in 1892 by the State of New Hampshire in accordance with joint resolutions of its legislature approved September 7, 1893, and August 25, 1885, with John Kimball, Erastus P. Jewell, and Joseph B. Walker serving as commissioners.