Alright, level with me here, I have never heard this phrase uttered in a conversation I hear in real life but I see it all the time online. It usually comes out as something like this: "They didn't have the [thing] I wanted, so I went to the next city to pick one up." I don't understand why it is referred to as "going to the next city." Where you live, are cities that far apart from each other? Are they that big? Do I just live in some crazy corner of the world where I could pass through four city limits in twenty minutes from where I live? The only time this seems to make sense is in situations where there is a great deal of rural land in between cities.

So tell me SEN, how far away do you live from "the next city over?" Is that actually a thing or is it just a generalization used online?

They didn't have an answer for me here, so I'll go check the next city to find one.

If you're explaining something locally, why would you say "the next city" when people would know exactly which city you'd be talking about when you specified it? If I told people here that I went to the "next city", they'd give me a weird look, and if I told people online that I went to "Kuna", they'd probably triangulate my position to stalk and/or kill me.

I don't think I've ever referred to a location by the city it is in unless it is at least forty minutes away... Landmarks, large shopping center names, street names is always more accurate.

There are least 3-4 cities that are within 15 minutes of where I live, so it's not uncommon to go from city-to-city looking for something. I'm pretty sure I've done that before. But I don't really consider those places cities (even though they technically are), so I've never used that phrase.

Imagine if you went to a retailer and they were out of stock, so you went to the location in another city. You had to travel between the "Best Buy" of each city (cities usually have just one?) and they're probably not very close to each other. I think that's how they're using it, at least in your example.

I've never heard this used personally, and I live in a metroplex.

We tend to live in urban areas where several cities have mashed in to each other, so cities sort of lose any sort of definite meaning. If you were to be in a rural area, each city may be too small for a lot of things (for example, children are bused from the entire area to one centrally located city to go to school), but they also aren't very far apart. Also a lot of people will live in one city and work in a different city in such cases (which if you think about it isn't really that weird since we do the same thing in urban areas).

So my guess is they don't live in a city, or perhaps is a phrase reminiscent of small-town life. My second guess (probably what Roy was saying) was they replace 'next city' with the specific city online so as to keep their location private.

EDIT:
Now that I think about it, it's definitely the second one. I hear people talking all the time at my job, and people are usually very specific about the city they went to in conversation.

O_O don't think it counts as a city if it has only one of a major retailer.

Just looked it up, this is false. Several Best Buys located in the same city for several cities in this state.

Not saying that it's valid, but are they in the same city or are they in the same metropolitan area? Like I could say there are several Best Buy's in Salt Lake, but really there's only one in Murray, one in West Jordan, one in Sandy, ...

Literally same city. their address uses the same city.

Closest city to my city is 2 hours away.