Togepi?

[drbasat]

So I just wonder, where are togepi come from?

In GSC and HGSS Professor Elm clearly states that Togepi is not Johto native.

What? That Pokemon! As far as I know there is not a Pokemon like this in Johto...

You can't get one in Hoenn, Unova or Kalos (friend safari). It's not native in Kanto or Johto, you get its egg as a gift. It was also a gift in Platinum. But you can actually catch one with poke radar in Route 230. It also gets its final evolution in Sinnoh so can we say Togepi is actually from Sinnoh?

Slugma, murkrow and houndour were Gen2 Pokemon that you can not catch in Johto. They were from Kanto.

 

[Joshawott]

Togepi can be found in the wild in Sinnoh's Route 230 and it's worth noting that Gen II and Gen IV are concurrent in the time line.

It's also worth pointing out that some animals become native to other regions after being introduced through the migration of humans. Perhaps a tourist or researcher came to Johto from the Sinnoh region with a Togepi egg and as such, it was something entirely new to Professor Elm (hence why he and Mr. Pokémon asked you to travel with it to help research it).

So effectively, Togepi was a Sinnoh-native Pokémon introduced to the Johto region, which became a part of Professor Elm's research. If you think of a regional Pokédex like an electronic method of a researcher recording and storing information about the Pokémon they research, then it makes sense that notes on Togepi and Togetic would be included with the rest of Elm and the GSC/HGSS player character's research - the Johto Pokédex.

In Generation V, Togepi can only be found in White Forest and in Generation VI, through the Friend Safari. Both areas increase the variety of Pokémon you can find through communication with other players, which could be the Pokémon world's equivalent of say, tropical spiders making their way to other countries through banana crates. So the only region that we've seen where Togepi can be found natively, is Sinnoh.

 

[Silktree]

So the only region that we've seen where Togepi can be found natively, is Sinnoh.

Even that is debatable. Togepi happens to be in the upgarded Sinnoh Pokédex (due to being given as an egg), but several Pokéradar-exclusive critters aren't. Pokémon that suddenly show up after the end credits strike me as gameplay elements more than anything else. They may not all be found in a Safari Zone-like place, but they may as well be. At least Black and White treated them as being the result of a Poké Transfer outbreak.

That said, there were several trainers in Platinum who used the Platinum line and Cynthia never said that Togepi was from another region, so I guess that the line is supposed to be native to Sinnoh.