By 1775, Brookline, with the rest of Massachusetts, was ready for greater independence from king and country across the water. William Dawes who rode along the Road to the Colleges (now Harvard Street) alerted Brookline that the British were marching on Concord. Three companies of Brookline volunteers mustered on the Town Green at the intersection of Walnut and Warren Streets and headed west, meeting the retreating British at North Cambridge and participating in their rout. One of their number, Isaac Gardner, was reportedly the only Harvard graduate among the patriots to die that day. The following spring, spurred on by John Goddard, a Brookline farmer and a fiery patriot who was to become Wagon-Master General for the Continental Army; the Brookline Town Meeting resolved that if "the Honorable Congress should, for the safety of the American Colonies, declare them independent of the Kingdom of Great Briton, then we. . . will solemnly engage with our Lives and fortune to support them."
Brookline's evolution from an agricultural to a suburban residential community began when wealthy merchants purchased large farms and built summer homes. Senator George Cabot and Samuel and Thomas Hanasyd Perkins were among the first, followed later in the nineteenth century by Theodore Lyman, John Lowell Gardner, Ignatius Sargent, Henry Lee, and Augustus Lowell. David Sears and Amos Lawrence were so taken with their Brookline estates that they gradually expanded them and laid them out as small communities where their friends, relations, and later buyers might join them in country living at Longwood or Cottage Farm.