Route 30 is the second route encountered by Trainers in Johto. From its southern terminus at Cherrygrove, the route turns northeast to avoid a ledge on the route that overlooks a patch of grass. Heading south, this ledge can be used to avoid the grass altogether.
The route emerges in an open area just north of the ledge. In the center of the area is a house owned by a man who is well-versed in the healing powers of Berries in Generation II, or Apricorns in Generation IV. To the left of his house is, incidentally, a Berry tree or Apricorn tree, respectively. West of the tree is a southbound-only path containing a ledge preventing northbound access. East of the house is a two-way path that runs along a small pond and through another area of grass.
North of the grass patch, the route comes to another open area. Here, Route 30 splits into two segments, a western path that leads to Route 31 and an eastern path that leads to the house of Mr. Pokémon. Initially, the player must take the east path north through a series of grassy areas to Mr. Pokémon's house, located in the northeast corner of the route, to meet Professor Oak and receive the Pokédex. Mr. Pokémon also gives the player an Egg to take to Professor Elm, which the player will receive once again in Violet City.
The western branch of the route is impassable until after the player has delivered the Mystery Egg to Professor Elm. Once this is complete, the player may continue northward, weaving around ledges and Trainers and passing through grassy areas towards Dark Cave and Route 31.
There is a small Cut-able tree near Mr. Pokémon's house that allows for passage between the two halves of the route, which is separated by a dense forest for most of the route.
In Pokémon HeartGold and SoulSilver, the pond behind the Cherrygrove City Pokémon Center is accessible through a new path and an extension of it on this route. However, this causes a strange phenomenon: as there is only information for one set of water Pokémon in a single location, one can find Tentacool and Tentacruel in the Cherrygrove City side of the pond (because they can be found in the ocean near the city). However, the Route 30 water Pokémon information only has Poliwag and Poliwhirl. This causes different Pokémon to appear in different sides of the pond. This also applies to fishing.
In the Generation II games, this pond existed, but was not accessible.