Japan consists of four main islands—Honshu, Hokkaido, Kyushu, and Skikoku—and has an area of 145,882 square miles (377,835 square kilometers), making it just smaller than Montana. The terrain is mountainous with most large cities along the coasts. The nation has a few active and many dormant volcanoes. Mild earthquakes are fairly common, and more destructive earthquakes hit every few years.

Japan has all four seasons. Winter can be very cold in the north, but to the south it is more tropical. Most of Japan is temperate with warm, humid summers and mild winters.

Japan's population of 127.4 million is shrinking by 0.01 percent annually. Nearly 70 percent of all people live in urban areas. Almost half are concentrated in three major metropolitan areas: Tokyo, Osaka, and Nagoya.