In Pokémon Crystal, Entei roams throughout the Johto region and changes its location after you encounter it, either by seeing it or by entering a new area. It typically moves to a different route or location when you enter a building or a new route. Entei's movements are random, making it challenging to track down. To effectively catch it, players often use methods like saving before encounters or using repels to manipulate its appearance.
Entei is a roaming Pokemon, so it can be on any route. Check your Pokedex to see Entei's location; it changes when you go into a new area.
route 202 u need to have entei and raiuko in your party
Route 45 is south of Blackthorn City.
You trade it with a girl on route 14 in crystal for a chansey, which can also be found in route 14
Route 38
route 29,49
route 14
I found Entei at route 38 but it will take a while to find Entei because legendary Pokemon are very very very hard to find.
Entei will appear if: You chose bulbuasaur as your starter Pokemon and if you beat the elite four obtained the national dex and gave the ruby and sapphire to celio. Once all of this is completed you can find Entei on any route where grass is, you can't find it on the islands. I suggest you go to Route 1 to find it because it usually goes there.
there is not 1 certain route and you have to of chose squirtle to get entei
An easy way is to duplicate your master ball (which is fairly simple, as it involves using the PC and another Pokemon.) and then buy a lot of max repels. Get a Pokemon near level 40 and put him/her/it in the first line. Use the Max Repels. Find a route where you can enter and leave the route with nearby grass. (Ecruteak City is a good start since by the south side of this city has nearby grass) Take about 20 steps in the grass with the repel. If no Pokemon appear, Raikou or Entei are not there. So leave the route by going back to Ecruteak and go back to the route. Take another 20 steps. Repeat this process until you eventually meet up with Entei or Raikou. If you run out of repel steps, use another repel. Duplication is different in Crystal. Turn the system off a split second after the r in power shows up.
Route 14, however, it is rare.