As of September 2016, the city has an estimated population of 49,523 and a population density of 230 persons per km2. The total area is 212.11 km2.
The city office is in Horobetsu. The town of Noboribetsu is at the mouth of the Noboribetsu river and is therefore a much narrower area.
Geography
The mountains dominate the west and north while the plains dominate around five km within the coastline. There are three towns along the Pacific Ocean: from northeast to southwest, Noboribetsu, Horobetsu and Washibetsu. These betsu are derived from "river" in the Ainu language. Noboribetsu is on the Noboribetsu River. Horobetsu and Washibetsu are on the Iburi-horobetsu River and the Washibetsu River respectively.
Origin of name
The name, Noboribetsu, derives from an Ainu word, nupur-pet, which means dark-colored river; the kanji 登別, meaning "climbing different", are used for their phonetic value only, and have no relation to the original meaning.
Climate
Climate data for Noboribetsu (1991−2020 normals, extremes 1977−present)
Jigokudani, or Hell Valley, the main source of the Noboribetsu onsen
6 km inland from Noboribetsu City in the river valley is the smaller town of Noboribetsu-onsen (登別温泉). The town has a range of onsen for bathing as well as other hot springs formed from different minerals for scenic viewing, and is also known for its bear park. Noboribetsu-onsen is one of many well-known resorts in Japan, with many hotels and ryokan, and is the largest "hot spring town" in Hokkaido. There is also the Noboribetsu Marine Park Nixe, the largest aquarium in Hokkaido.