Clay Tunnel (Japanese: ヤーコンロード Yakon Road) is a cave in the western half of the Unova region, exclusive to Black 2 and White 2. It connects Driftveil City, Twist Mountain, Mistralton Cave, and Underground Ruins. It can be accessed once the player has entered the Hall of Fame. The tunnel was named Clay Tunnel after the Driftveil City Gym Leader, Clay.
Mine carts connect the different areas of the cave system, and these can be used by talking to the various workmen inside the cave.