Many Older Pokémon Have An Unknown Catch Location in 'Pokémon GO' For This Reason

The gist:

• Some older Pokémon have a catch location of "unknown."
• It's suspected these Pokémon are from some of the first research tasks in 2018, as those often were caught without a listed catch location.
• There are other explanations if your Pokémon is not from 2018.

With Pokémon GO being a game that takes place internationally, the game has put plenty of measures in place to let you keep track of all of the stats of the different Pokémon you catch. There are the average stats, like height and weight, but each Pokémon in your inventory will usually also list what day and where you caught it.

Occasionally, trainers have found that a Pokémon in their inventory will have "unknown" listed in the caught location category — but how does this happen?

There are a few different hypotheses as to why certain Pokémon have their catch location listed as "unknown," though it seems to have to do with research tasks in Pokémon GO. Since the mobile AR game came out in 2016, there have been plenty of improvements made since its release. Some trainers suspect that Pokémon tied to early research tasks are notorious for not having a listed catch location.

"There was a period where any research Pokemon did not register a catch location," one Reddit user replied in response to a question about this incident. "This has been fixed now, but these Pokemon still don't have any location data so it says Unknown."

Oftentimes, when completing a research task (whether field or special), you may be rewarded with the opportunity to catch a Pokémon tied to that task. These tasks weren't implemented into regular gameplay until 2018, and plenty of the Pokémon with an "unknown" catch location were acquired around this year.

That said, this is not as cut-and-dry an answer to this problem trainers are finding. Not all of the Pokémon with the "unknown" catch location were caught in the same year. Those with even older or more recent Pokémon are also still finding this issue.

"If the surrounding gym[s] or PokéStops have been deleted, they either reclassify it to a larger nearby city or label it as unknown," one Reddit user theorized.

Others have suspected it has something to do with the reliability of your phone's GPS. Some players have reported having issues where the catch location is often wrong, listing different cities than where the Pokémon was actually caught. Others have suspected it may have to do with certain restrictions in countries.

"I have some from when I was out at sea. Most are blank, but also have unknown, in all caps," one Reddit user wrote, while another replied "Did you travel to a geo-locked area recently? I have a few from China with [an] unknown location."

Unfortunately, despite many of these bugs being patched since the game launched, it doesn't seem as though there's a way to go back and update the caught location. However, if any of these Pokémon in your inventory have an "unknown" catch location and are from 2018, consider holding onto them for trading purposes, as older Pokémon are more likely to result in lucky trades.