For many years there were no permanent residents on the Ogasawara Islands, and it was nothing more than a haven for castaways and a port for foreign ships. In 1830 the first settlers arrived from Oahu in Hawaii, comprised of westerners and native Hawaiians. (Ref. 1) Subsequently, in 1862 the Shogunate decided to develop and settle the islands, with the result that 38 people moved to Chichijima. (Ref. 2)

From the Meiji period (1868-1912) the population increased and by 1907 the total population numbered approximately 4,000 people. It continued to grow to the extent that by 1921 there were more than 6,000 residents. (Ref. 3) Thereafter, although there were slight fluctuations, the pre-war entire population of the islands remained on an upward trend. (Ref. 4) 

In 1944, due to changes of the war situation the former Imperial Japanese Army ordered the forced evacuation of 6,886 residents to the mainland. The remaining soldiers on the islands were also repatriated to the mainland by U.S. Forces following the end of the war. (Ref. 5) 

At the time of the reversion in 1968 the population was 181, but it had approximately tripled to 540 by the end of March 1969. However, the number of native islanders decreased to 172, due to death, relocation and other reasons. (Ref. 6) 

Thereafter, with the introduction of plans to promote returning to the Islands, from around 1975 the population began to increase rapidly, and up to around 1996 the population continued to grow steadily. Although there was a first decrease in the population in 1997, it subsequently increased again, and since around 2000 the population has remained largely the same, with slight fluctuations. As of April 1, 2019, according to the basic resident register for Ogasawara Village, the population of Chichijima and Hahajima combined is 2,615 people (including foreign residents). (Ref. 7) 
 

Ref. 1: Francis L. Hawks (compiled by), Narrative of the expedition of an American squadron to the China seas and Japan, performed in the years 1852, 1853, and 1854, under the command of Commodore M. C. Perry, United States Navy, Washington: A. O. P. Nicholson, 1856, p.200.

Ref. 2: “The matter concerning the development and revitalization of the Ogasawara Islands 9,” Tsushin-zenran (Complete List of Diplomatic Notes and Correspondence), Compilation by category, Miscellaneous 1296 
(Repository: Diplomatic Archives of the Ministry of Foreign Affairs of Japan)

Ref. 3: An outline of Ogasawara Shoto (Tokyo Prefecture), pp. 120-128

Ref. 4: Nanpo Doho Engokai, Ogasawara kankei shiryo (Documents Relating to Ogasawara), 1959, pp. 16-23.

Ref. 5: Ishii Michinori, Ogasawara shoto gaishi (sono 1): Nichibei kosho wo chushin toshite (A Brief History of the Ogasawara Islands (Part 1): Focusing on Japan-U.S. Negotiations), Nanpo Doho Engokai,1967, pp. 27-30.

Ref. 6: Ogasawara Association, Ogasawara shoto chosa hokokusho (Report on the Survey of the Ogasawara Islands), 1969, p. 5.

Ref. 7: Tokyo Metropolitan Ogasawara Branch Office, Kannai Gaiyo (Overview of the Jurisdiction), 2019 ed., pp.27-32.