The K Line Northern Extension, formerly known as the Crenshaw Northern Extension, is a planned Los Angeles Metro Rail light rail extension connecting Expo/Crenshaw station to Hollywood/Highland station in Hollywood. The corridor is a fully underground, north–south route along mostly densely populated areas on the western side of the Los Angeles Basin; it would be operated as part of the K Line. The Los Angeles County Metropolitan Transportation Authority (Metro) is prioritizing the project along with pressure from the West Hollywood residents. Construction is slated to start in 2041 and begin service by 2047 unless means to accelerate the project are found.
On July 23, 2024, LA Metro released the draft of the Environmental Impact Report (EIR) for the K Line Northern Extension, putting the price tag of the project between $11 billion and $14.8 billion (including a 40% contingency cost).