Yomiyama City is the main location of the series. Almost the whole plot of the series takes place in Yomiyama. Most of the locations are within this city (including the Sakitani Kinenkan and but excluding The Beach) and all the characters (excluding Kouichi Sakakibara, who was only born here) are from this city. This location was first seen in"Rough Sketch", after Kouichi came to Yomiyama to live with his mother's family.
- It was initially believed the calamity was confined to Yomiyama and once the students and their families had escaped the city, they would be safe. Junta Nakao's death seemed to disprove this at first, until it was learned he'd suffered an aneurysm while still in the city, which burst at the beach and killed him. With this in mind, the Inn, where the vast majority of the 1998's calamity's deaths took place, is within the borders of Yomiyama.