Location from pokemon-unova by
Unova's snowbound northern city — home of Brycen's Ice Gym, Dragonspiral Tower's base, and a lot of very bored Vanillite.
Icirrus is cold and quiet. Brycen runs the Gym like a shrine. Dragonspiral Tower, the ancient structure where Reshiram or Zekrom sleeps, is accessible from here — it's where the Hero-of-Ideals/Truth sequence culminates in the climax. Iris specifically does not like Icirrus for its temperature and Ice-type concentration, a running gag.
Low wooden buildings with steep snow-shed roofs, wood-burning stoves venting smoke into a white sky. Cobblestone streets kept clear by human shovels and Vanillite foraging. A dark silhouette on the northern horizon: Dragonspiral Tower.