[funkymike]

Where I am from cities cannot legally cross county boundaries. But the people who live just across the county line still have a postal address with the name of the city because doing anything else would not make sense on a practical level. In fact I'm not sure if they are technically in a city at all.

[umanwizard]

Cities can cross county boundaries in some states, though -- NYC, for example, contains five counties within its city borders.