Sometime between 1831 and 1833, Carleton County was set off from York County and a Shire Town (county seat) was established in the Town of Woodstock. Today, Woodstock is by far the largest municipality in Carleton County and is also home of the Woodstock First Nation. You'll still find the Old Carleton County Courthouse, built in 1833.
You may also learn more on the Provincial Archives web site.
(Ruth, the rest is up to you. Post some pictures and information)