From its junction with Route 12, Route 11 passes over a short bridge before heading west through a clearing in the forest that lines the west side of Route 12. The route becomes more built-up as it approaches a gate, becoming fenced on each side. This station is seen by some as the eastern terminus of Route 11.
West of the station, the route is completely surrounded by grass patches. To avoid encounters with wild Pokémon, Trainers can follow beaten dirt paths through the field. The first such path begins just west of the gate. The path turns south before resuming a westward alignment and turning north to intersect a short path that travels to the west. The main path continues north, then west to come to a near four-way intersection. The north and south paths ultimately lead to a dead end surrounded by grass while the west path continues toward Vermilion.
Several paces west of the four-way intersection is another three-way junction. The two routes, which isolate a small patch of grass from the rest of the route, rejoin east of Diglett's Cave. In Generation I and Generation III, the route runs along the north bank of a narrow channel as it meets the southern portal of Diglett's Cave and enters Vermilion. In Generation II, however, the junction that rejoins the two routes is located just east of the Vermilion City limits. The river is also non-existent and Diglett's Cave actually emerges in east Vermilion.
In Generation IV, the southwestern exit leads to Vermilion City's eastern harbor.
At the east end of Route 11 is a sleeping Snorlax, blocking not only Route 11 but also Route 12. To move it, a Trainer must play the Poké Flute to awaken the Pokémon.
In the most noticeable change, the number of Trainers on the route had been cut from ten to four. Just as noticeable is the removal of the gate on the east end of Route 11 and the moving of Diglett's Cave from Route 11 to Vermilion City.
The layout of the route is different to previous generations. The Snorlax blocking the intersection between Routes 11 and 12 has been moved to the front of Diglett's Cave (which is now part of the route again instead of Vermilion as in Generation II). The method of moving Snorlax is the same as the Generation II games. A new hill is added in the west, before the entrance to Vermilion City. The road that goes through the tall grass is designed differently. The gate is present unlike Generation II. Fences are added as well as a new section at the southwest that leads to a new part of Vermilion. A signpost is added near the gate and the Berry tree, now replaced by an Apricorn tree containing a Grn Apricorn, has moved to the center of the route. Most of the trees placed in this route are backwards, as well as several other textures, compared to other locations.
Next Red decided to take a shortcut through a forest. Though a Bug Catcher warned Red not to enter the forest without a Repel, Red instead used his Pikachu's Thunder Shock to defeat all the Bug Pokémon they came across and Bulbasaur's Razor Leaf to cut through the dense trees. At one point, Bulbasaur accidentally attacked a Beedrill nest, causing Red and his Pokémon to be attacked by a swarm of angry Poison Bee Pokémon. Despite this setback, Red managed to bypass many competitors who hadn't taken the shortcut.