Whitney (Akane in original Japanese language versions) is in charge of the Plain Badge, and resides in Goldenrod City. (The Plain Badge's name is a pun in English; Whitney lives on a rural Midwestern-esque farm, and is also a trainer of Normal-type Pokémon.) She is an expert on Normal types. Whitney's name in English means white islands. It was probably chosen because "white" relates to being without color and therefore plain and normal. Her Japanese name, Akane, can be taken to mean madder (a type of plant) or deep red (possibly related to her hair color). Whitney's signature Pokémon is a particularly tough Miltank.
In the anime
Whitney is the niece of a Miltank farmer, has the unique ability to always take the right path to wherever she needs to go, as long as she has no idea how to get to her destination, and is also noted for her clumsiness. She ends up leading Ash and his friends on a wild goose chase through Goldenrod City, ending at the Goldenrod Galleria, before Ash realizes that she is the gym leader. They battle, but after defeating her Nidorina and Clefairy, Ash's Pokémon turn out to be no match for Whitney's Miltank. After working at Whitney's uncle's farm for a bit and foiling a Team Rocket scheme, he earns a rematch with Whitney, where Pikachu outmaneuvers and knocks out her Miltank.
In the manga
In Pokémon Adventures, Whitney is an actress who is good friends with DJ Mary (to whom she gave a Smeargle). She met Gold while performing at the Radio Tower in Goldenrod City, but the two clashed and ended up competing against each other in a bike race. Whitney isn't a strong Gym Leader, according to Suicune, and is the one of two Johto Gym Leaders (along with Pryce) that Suicune doesn't challenge for the right to be its partner in the fight against the Mask of Ice. In the end, she was the first to realize that Pryce was the villain known as the Mask of Ice. Whitney has a Cleffa and Igglybuff who work together to stun and confuse enemies to set them up for Miltank's attacks. At one point she also has a particularly mischievous Smeargle, but she gives it away. She faces Misty at the Pokémon League and loses due to a Hyper Beam from Starmie.