In 1774 he was appointed colonel of a regiment of “minute men,” enrolled in Pepperell and vicinity. On receiving intelligence of the “regulars’” (British) attack on Lexington on the memorable 19th of April, 1775, the alarm that was raised, that British troops were marching on Concord reached Pepperell about 10 a.m. on April 19. Prescott immediately gave order for the company in Pepperell and the company in Hollis, to march to Groton and thence to the scene of action, but arriving there before the Groton Companies were ready, they, after a short halt, proceeded on their way in advance of the Groton companies. Col. Prescott hastened on, with as many of his regiment as he could collect, to Concord and thence to Cambridge, but did not overtake the retreating British troops. The companies arrived too late to participate in the day's battles, but they became part of the small army that laid siege to Boston afterward. He and most of his men enlisted for eight months, the period of the first enlistment.