Here are some links to several places where queries can be posted.
Check out the Places page if you are not certain if the location is in Carleton County.
Carleton County
This one is specifically for Carleton County. If your query involves other counties, post it there, too. Responses involving the other county should be posted to that county's query page.
Ontario - general
Use when you know the province is Ontario but are uncertain of the correct site in Ontario. This includes Upper Canada and Canada West.
Canada - unknown
Use when the location is known as Canada or the province is unknown.