On April 27, 1775, when word of the Battles at Lexington and Concord reached the Suncook Valley in New Hampshire, McClary was busy plowing land back on his farm. He and other patriots gathered and "flew to arms" and assembled at Nottingham Square. There they made Captain McClary commander of the company consisting of eighty men. They departed from Nottingham Square at one o'clock in the afternoon and conducted a "rapid march" south to Kingston. From there they continued at a fast pace without resting until sunset, arriving at Haverhill, just over the Massachusetts border on the Merrimack River. McClary's company covered twenty-seven miles in six hours. They continued for a few more miles then stopped and took supper at Andover. After resting a bit they resumed marching through the night and by sunrise had covered seventy miles distance. After passing through Medford, they continued south and marched on Cambridge Common where upon arrival were all willing and eager to fight for the Revolution. There McClary and his company joined up with Colonel John Stark, who gave McClary the rank of major. On June 16 they received orders to join with American forces and prepare for battle at Bunker Hill, in Charlestown across the Mystic River from Boston. The battle was to take place on the Charleston Peninsula which was only accessible to American infantry by crossing over the very narrow Charleston Neck.