Karuizawa is one of Japan's most established highland resort towns in Nagano Prefecture, widely known for its cool climate, forested landscape, and long-standing second-home culture. The town combines resort identity with everyday livability, which is why it attracts both seasonal residents and year-round households.

Its character is defined by low-density development, large land parcels, and strong emphasis on site quality, privacy, and natural surroundings. Sub-areas within Karuizawa can feel very different in atmosphere and built form, from quieter residential pockets to busier commercial and station-adjacent zones.

As of March 1, 2026, official population is 21,759 across 11,265 households. In practical terms, Karuizawa is a lifestyle-led town where climate, topography, road access, and neighborhood character shape how people choose where to live.