Route 1FireRed&LeafGreen
"The walk from Pallet Town to Viridian City. Nothing dangerous, just Pidgey and Rattata for your first catches before you get Poke Balls from Oak's parcel delivery."
ROUTE 1 MAP
Straight north-south path between Pallet Town and Viridian City. No turns, no branches, and no HM requirements. One of the simplest walks in Kanto.
Pokemon Encounters
Just Pidgey and Rattata, split 50/50 at levels 2 to 5. Pidgey evolves into a reliable Flying-type later. Nothing else spawns here, grab one of each and move on.
Pidgey
Also found in 15 other locations
Route 1 Guide
Yes. Several routes have version-exclusive encounters. FireRed gets Oddish, Growlithe, Scyther, and Electabuzz in certain areas, while LeafGreen gets Bellsprout, Vulpix, Pinsir, and Magmar. Check the encounter table for this route and look for the version tag next to each Pokemon.
After battling a trainer, walk 100 steps to recharge it, then use it while standing on the route. Nearby trainers ready for a rematch get an exclamation mark over their head. Rematched trainers carry stronger teams as you progress through the game. You get the VS Seeker from a girl in the Vermilion City Pokemon Center.