The fighting that raged over miles of Massachusetts countryside on April 19, 1775 finally subsided with the approach of evening. Thousands of Massachusetts militia had converged upon retreating British troops as they made their way back from Concord that fateful spring day and the casualties suffered by the redcoats were shocking. Two hundred and seventy-two officers and men were killed, wounded, or captured on the march from Concord. Over ninety militia from twenty-three different communities also fell that day, a majority of them killed.[1]

Although the redcoats intended to return to Boston, their commander Gen. Hugh Earl Percy decided late in the day to march to Charlestown, instead. Percy had taken charge of the British force in Lexington when his brigade united with Lt. Col. Francis Smith’s original detachment. Charlestown was located on a peninsula across the Charles River from Boston and Percy expected that the Mystic and Charles Rivers would finally protect his flanks, which had been ravaged by the militia for much of the march. He also believed that the narrow passage connecting the peninsula to the mainland would provide a strong position for his exhausted troops to repulse any further attacks by the militia.

Gen. William Heath, the ranking militia general engaged in the battle on April 19, recognized the danger and futility of advancing onto the peninsula and ended the militia’s pursuit outside of Charlestown. He posted a strong guard on high ground overlooking the neck of the peninsula and ordered patrols to be vigilant all night in case the British attempted to advance from Charlestown. He then ordered the remainder of the militia, numbering in the thousands to, “lie on their arms” below Cambridge.[2]