Rufus Putnam was born on April 9, 1738, in Sutton, Massachusetts, the son of Elisha Putnam and Susanna Fuller. After the death of his father, Putnam lived with relatives until he started his apprenticeship as a millwright in 1754. He served in the French and Indian War, received a promotion to sergeant in 1759, and taught himself the basics of military engineering. Putnam became a millwright in 1761. In the 1760s and 1770s, Putnam taught himself land surveying while he worked as a miller and farmer in Massachusetts. He oversaw the construction of defensive works around Boston from 1775 to 1776, and around New York in late 1776 (including West Point). He earned the rank of colonel in the Continental Army in 1776 and became brigadier general by January 1784.
Congress appointed Putnam a surveyor of the lands northwest of the Ohio River because of his extensive military career and his skill as a land surveyor. In March 1786, Rufus Putnam and Benjamin Tupper created the Ohio Company of Associates, with the purpose of organizing a group of like-minded individuals interested in settling land west of the Appalachian Mountains. The Ohio Company bought 1.5 million acres of land from Congress. Putnam led a group of Ohio Company men to the Muskingum River in 1788, and oversaw the construction of the town of Marietta, including a fort and a plan for a city of fifteen thousand occupants. Putnam's role in the Ohio Company and the settling of Marietta helped him gain recognition in both the territorial and national governments. In 1790, President George Washington appointed him a territorial judge and, on October 1, 1796, surveyor-general of the United States. As surveyor-general, Putnam oversaw the establishment of the Indian-United States boundary line described by the Treaty of Greenville. After Thomas Jefferson became surveyor-general in 1803, Putnam remained in Marietta, and helped found Ohio University in Athens (1804). He died in Marietta in 1824.
Rufus Putnam married his first wife, Elizabeth Ayres of Brookfield, Massachusetts, in 1761, but she died later the same year. Rufus Putnam married Persis Rice (d. 1820) of Westborough, Massachusetts, in 1765, and they had nine children.