Pokemon Ash% Catch Locations

Caterpie: Viridian Forest
Metapod: Evolve Caterpie to Level 7
Butterfree: Evolve Butterfree to Level 10

Pidgeotto: Route 5, Route 6, Route 7, Route 8, Route 11, Route 12, Route 13, Route 14, Route 15, Route 21, Route 24, Route 25, Viridian Forest [Best to get it on Route 15, because they’re all level 32, which is the closest level to 36… or get 2, one for Flying the other for evolving? Hmmm…]
Pidgeot?: Evolve Pidgeotto to Level 36

Bulbasaur: Cerulean City, make Pikachu super happy
Squirtle: Vermillion City, talk to Officer Jenny after beating Lt. Surge

Charmander: Route 24 (right after Nugget Bridge), talk to guy to left of random item
Charmeleon: Evolve Charmander to Level 16
Charizard: Evolve Charmeleon to Level 36

Raticate: Route 5, Route 6, Route 7, Route 8, Route 11, Route 12, Route 13, Route 14, Route 15, Route 21, Route 24, Route 25, Viridian Forest
Tauros: Safari Zone Areas 2 + 4
Primape: Route 23 (can go to the grass after you get 6 badges if you really want)
Muk: Power Plant, Pokemon Mansion (except the 1st floor)

Krabby: Route 10 (Fishing w/Super Rod), 25 (Fishing w/Super Rod), Seafoam Islands (Walking and Fishing w/ Super Rod) [Best to get it in Seafoam Islands then give him a rare candy, especially in the lower floors Krabbys are around the level 28 range]
Kingler: Evolve Krabby to Level 28, Route 10 (Fishing w/Super Rod), 25 (Fishing w/Super Rod), Seafoam Islands (Walking and Fishing w/ Super Rod)