Route 42

21 Pokémon can be caught at Route 42 in Johto — highlighted on the map below.

Route 42 runs along northern Johto between Ecruteak City and Mahogany Town, with several entrances to Mt. Mortar dotted along its length. Small lakes cut the route in two places, so travelers need Surf to cross unless they detour through the mountain itself. A cuttable tree on the central landmass opens the way to three Apricorn trees. In Crystal, HeartGold, and SoulSilver, Suicune can be spotted near those trees before darting away as the player approaches.