Sign-in notification location is in my time-zone, but far from my location (a northern US state vs Sao Paulo, Brazil). So, I'm running on a South American network?? Please advise.?

When I sign-in to my iPad or iPhone, I am sent the Apple ID Verification code. But before I can see it, I get a message saying "Apple ID Sign In Requested - Your Apple ID is being used to sign in to a device near Sao Paulo, SP." The screen that follows asks if I will "allow / don't allow". If I don't, I can't sign in. But if I do, who else is accessing my info? Or am I really on a network in South America, when I'm an hour's drive from the Canadian border? Please explain.