iPhone picks up Rogers when traveling in Maine

You don't need to be in Canada. When I had Verizon, if I visited my grandmother in VT, I had to make sure to always go to the kitchen to answer a call. If I was in the front of the house, I'd get a Canadian tower and be charged international rates.

When your phone picks up an international tower, you are charged an international rate for using an out of the country tower. That tower may have a stronger signal that an ATT tower in your area and be overriding the ATT signal.

I don't know if there is a way to improve service or reception with Rogers when close to the Canadian border, but I think not.

You do know you will be charged international roaming fees when placing or receiving calls, the same for SMS, and when accessing the internet via the cellular network when your iPhone is connected to Rogers, which is isn't cheap?

I live in a town beside Lubec, Maine. I have the same problem. I have plenty of bars when it says "ROGERS" but I can only occasionally send an SMS. most of the time from the same place (my house) I get no service or a single bar of "AT&T". Why does it do this? I'm not in Canada! Canada is at least 30 miles from my house. Why would I be charged more? And if I do have this "ROGERS" service why cant I at least consistently send an SMS or make a call?
P.S. what were you doing in Lubec?

You could always just set the iPhone rather than automatic for network to only AT&T in Settings>Network Selection this should stop the phone from roaming onto another carriers network and the fees associated with this.
You can do the same for data in Settings>General>Network>Data Roaming "off"
These options would bypass the issue, while you wouldn't necessarily get as good an coverage at least you wouldnt get billed

Geez that's a bit silly really. Here the iPhone is network locked (though it can be unlocked by the carrier) but it still gives us that option i suppose it's because we don't have roaming as such on carriers here. If i'm with Telstra i only use Telstra's network and the same for the other carriers, the only time that changes is if you go from 3G to GSM then dependant on your carrier you will roam on another network because your carrier might not have a GSM network (though there are no additional fees for this).

Has anyone found a solution to this? I'm visiting my parents in Robbinston Maine this week and have the same problem. I'd live to set my phone to At&t only if anyone has found a way. I keep on picking up the Rogers towers

The US iPhone does not have a Network Selection option.

It's definitely a pain for people who live close to the Canadian border.

What about under Setting>Carrier can you turn off automatic?

We don't have that option.