The history of Napanee began in 1784 with the settlement of the King's Regiment of New York and their families following the conclusion of the war with the American Colonies. In 1785, a saw mill was erected on the river near the falls and a year later, a grist mill. By 1830, Napanee boasted almost two dozen buildings and was slowly developing as a port, exporting timber, grain, wool and potash. By the 1850s, Napanee had changed from hamlet to a village and in 1852 became a "police village" (meaning it could tax the community to pay for the services of a constable). In 1855, the village was incorporated as an independent municipality. When the Grand Trunk Railway arrived in 1856, Napnee's economy gained impetus and, with its resulting growth in size and importance, became the County Seat for Lennox and Addington County in 1863.

Due to an abundance of water power, Napanee experienced its greatest growth during the period of industrial expansion between 1870 and 1880. The added prosperity of the merchants and industrialists at the tine resulted in the construction of many residences that today give Napanee its rich architectural heritage.

By 1990, Napanee was a quieter place with a static population consisting of civil servants, officials, merchants and retired farmers. Even with renewed growth during the war and post war years, the character of the town has remained virtually unchanged. Unlike many larger urban centres, where redevelopment has destroyed much of the architectural heritage, Napanee has been able to retain its past in the form of graceful buildings that still reflect the charm of an earlier era when the place was slower and life was simpler