when was the last town established?
1796
West Turin, New York
The town was first settled around 1796, near Constableville. 
which places are connected by new york state route 12d? Oneida County village of Boonville; and Lewis County village of Lyons Falls. since how may years is the route being used? 113 years (since 1908) which places does the route pass through? Sugar River, Locust Grove community, West Turin
wiki:18747805
West Turin, New York [SEP] History
The town was first settled around 1796, near Constableville. West Turin was formed from part of Turin in 1830 and was subsequently reduced in size by the formation of newer towns: Montague (1850) and Osceola (1844). The town of West Turin now includes the former "Town of Highmarket", which was disbanded in 1973. Highmarket had been set apart from West Turin in 1852.