There’s one street in Summer Village of Castle Island, Alberta - CityStrides and it was marked as private some time between being added to CityStrides and now
I’m wondering if anyone local can confirm the whole street is private Way: Castle Island Road (427288824) | OpenStreetMap … nothing in Castle Island, Alberta - Wikipedia suggests it’s private but 
My brother in law lives about 10 minutes from Castle Island and says it is private with a gate requiring a code to get on the road. Google Maps streetview also shows the gate. I have not been there in person to check it out though.
That’s very convincing proof, imho