Atsugi (厚木市, Atsugi-shi) is a city located in Kanagawa Prefecture, Japan. As of 1 June 2021[update], the city had an estimated population of 223,960 and a population density of 2400 persons per km². The total area of the city is 93.83 square kilometres (36.23 sq mi).
While the name "Atsugi" is often associated with the United States Navy base named Naval Air Facility Atsugi, the base is actually not in Atsugi, but straddles the border between the nearby cities of Ayase and Yamato.
Atsugi is located in the hilly center of Kanagawa Prefecture, approximately 45 kilometres (28 mi) from central Tokyo or 30 kilometres (19 mi) from central Yokohama. It is located at the northern end of the Sagami Plain created by the Sagami River, which originates from Lake Yamanaka, and straddles the Tanzawa Mountains in the west and the plain on the west bank of the Sagami River to the southeast. The Nakatsu River and Koayu River, which originate from the Higashitanzawa Mountains, join the Sagami River, which forms the border with Ebina, Zama, and Sagamihara. Parts of the western portion of the city are within the Tanzawa-Ōyama Quasi-National Park and include Mount Ōyama.