Warabi is a city located in Saitama Prefecture, Japan. As of 1 February 2024, the city had an estimated population of 75,614 in 41,025 households and a population density of 15,000 persons per km2. The total area of the city is 5.11 square kilometres. Warabi has the smallest area of any municipality in Japan, and highest population density outside of the special wards of Tokyo.