By the 1860s, the population of the Lennox & Addington region had grown to more than 15,000 and the movement to separate from The United Counties of Frontenac Lennox & Addington intensified.
Led by John Stevenson, a wealthy Napanee lumberman and Reformer, the Lennox-Addington lobby won its case and separation from Frontenac was granted in 1863 by an Act of the Government of Canada.
Napanee, Newburgh, Tamworth, and Bath all vied for the honour of becoming the County Town. In the election of 1863, the Conservative member, Augustus Hooper, a merchant from Newburgh who defended Newburgh as a choice, lost to an independent, Richard Cartwright, who backed by Napanee's mercantile community, endorsed Napanee as the County Town. Napanee was finally chosen and a courthouse and jail were built in 1864 at the head of Adelphi Street, on land donated by Cartwright.
In recognition of his leadership during the separation dispute, John Stevenson was chosen County Warden from 1863-1865 and in 1867 went on to become a member of Ontario's Legislative Assembly where he became Speaker of the House.
The new county was optimistic about its future. The Addington Colonization Road, from Tamworth to Denbigh, expanded the hinterland and settlement northward into the Shield. Schools, churches and small mercantiles continued to multiply, fostering a greater sense of community. By the end of the decade, construction of a railway to link the communities along the Napanee River Valley by rail had begun, although it would be the next decade before the Napanee, Tamworth and Quebec railway trains travelled regularly between the communities.
