Why is Coffeyville, KS in my GA4 report?

We’ve all been here before.

A few months ago, I was on a client call discussing our monthly reporting. I had just finished presenting the SEO section—fantastic numbers, by the way—and handed it over to my colleagues for their parts of the presentation.

While our analytics team was discussing geo data, the client interrupted and asked, "Why are we getting traffic from Coffeyville?" Honestly, I didn't know the answer, and it was the first time I had heard about it. My colleague also didn't respond immediately, which left the client unimpressed and us scrambling on our Slack channel.

Two thoughts crossed my mind:

1) We should have had an answer prepared.

2) Where the heck is Coffeyville?

After a quick Google search, I discovered that Coffeyville is an actual town in Kansas. Our client was based in Chicago, and I doubt we target Kansas users. So, what's the deal?

Coegi describes the "Coffeyville Effect" as a phenomenon that arises when location data is unavailable. If you observe traffic from Coffeyville, KS, in your reports, it is likely due to a problem with one of Google's third-party data providers rather than an issue with Google itself. Google collaborates with companies like MaxMind and Digital Element for IP-based geolocation.

When Google processes traffic data, it sends IP addresses to a third-party source to determine location. If the provider successfully matches the visitor's location, GA4 populates the appropriate fields. However, if the provider cannot determine the location, it marks the fields as "(not set)" and defaults the location to the geographic center of the U.S., which happens to be Coffeyville. Thanks, Google.

So, what can you do? You can try different filters to get a more accurate view of your data and filter out unnecessary traffic. Create a custom filter to exclude "Coffeyville," which should eliminate false traffic from that region.

But the most important thing to remember is this:

Do not panic--your ad dollars are safe, your campaign isn't failing, and your website is likely functioning perfectly fine. Explain this strange phenomenon to your team and client, reassure them that everything is okay, propose a plan to filter out this traffic, and go from there.

Then again, Coffeyville has a population of nearly 10,000—maybe a few of them are interested in your brand!