Little is known of the early history of Korsakov. The site was once home to an Ainu fishing village called Kushunkotan (in Russian sources, Tamari-Aniva), which was frequented by traders of the Matsumae clan from as early as 1790. On September 22, 1853, a Russian expedition, commanded by Gennady Nevelskoy, raised the Russian flag at the settlement and renamed it "Fort Muravyovsky", after Governor-General of Eastern Siberia Nikolay Muravyov. Nevelskoy left detailed recollections of the landing. He encountered a predominantly Ainu population (at least 600 people; another source mentions only 300 Ainu inhabitants) as well as Japanese nationals who, judging by Nevelskoy's account, exercised authority over the native inhabitants. At the time of Nevelskoy's arrival, the village featured several standing structures—Nevelskoy calls them "sheds"—and even a Japanese religious temple. The villagers supposedly welcomed the Russians after they learned about their mission (protecting them from foreign incursion). Of course, the veracity of this account is in doubt, both because Nevelskoy had ulterior motives for claiming that he was "welcomed" by the inhabitants, and also because it is not clear to what extent the Russians were able to make themselves understood. The Russians abandoned the settlement on May 30, 1854, allegedly because their presence there, at the time of the Crimean War, raised the specter of Anglo-French attack, but returned in August 1869, now renaming the town "fort Korsakovsky," in honor of then-Governor General of Eastern Siberia Mikhail Korsakov. Lingering territorial conflict between Japan and Russia has polarized scholarly opinion of Korsakov's early history, as each side tries to claim priority of early settlement to back up their respective territorial claims in the broader region. In 1875, the whole Sakhalin including the village was ceded to Russia, under the Treaty of Saint Petersburg.
While under Russian administration fort Korsakovsky was an important administrative center in Sakhalin's penal servitude system and a final destination for hundreds of prisoners from European Russia, sentenced to forced labor for particularly serious crimes. Such prisoners and their families comprised early settlers of fort Korsakovsky until its hand-over to the Japanese. Prominent Russian writers, including A.P. Chekhov and V.M. Doroshevich, visited Korsakovsky and left keen observations of its unsavory trade.
In 1905, Korsakovsky was handed over to Japan after Russia's defeat in the Russo-Japanese war of 1904–1905. Renamed Ōtomari, it was temporarily the capital of Karafuto Prefecture between 1905 and 1907. While in Japanese hands the town grew substantially. Upon the ashes of fort Korsakovsky (the Russians burned the wooden town before the hand-over) the Japanese built a stone-clad modern city, with paved streets and electricity.
A penal colony under Russia's administration, Ōtomari maintained the dreadful practice of forced labor: thousands of ethnic Koreans were brought over as slave workers. Korsakov's present-day Korean population are mainly descendants of these labour conscripts.
After World War II, Ōtomari was again ceded from Japan, this time to the Soviet Union. The Japanese population was mostly repatriated by 1947, though a few remained, along with a sizable Korean population. Old Ōtomari burned down substantially with the entry of the Russian troops. The old Bank, Japanese bank building (originally, Ōtomari Branch of Hokkaido Takushoku Bank) remains standing today, though efforts to convert it to a museum came to nothing for lack of funds. Other Japanese sites and memorials were all destroyed, including a Shinto shrine and a monument to Prince Hirohito who had visited Ōtomari on an inspection tour. An interesting sample of Japanese monuments can now be seen near Prigorodnoye (Merei before 1945)- a fallen stella to Japanese soldiers.
Within the framework of administrative divisions, Korsakov serves as the administrative center of Korsakovsky District and is subordinated to it. As a municipal division, the town of Korsakov and seventeen rural localities of Korsakovsky District are incorporated as Korsakovsky Urban Okrug.
According to a November 1, 1945 Soviet reports, the town had:
Up until the 1990s, Korsakov was a major base for the Russian Far Eastern fishing fleet. It was the home of the Base for Ocean Shipping—Baza Okeanicheskogo Rybolovstva—which, however, went bankrupt during the post-Soviet recession, perhaps for no better reason than downright looting of state property. The thousands of fishermen employed in the "Bor" continued their work for private fishing companies, which usually operated small fishing boats not far off the coast, often without licenses. The catch (primarily crab) was sold in Japan for hard currency, mainly in Wakkanai. Fishermen purchased Japanese electronics and used cars. This semi-illicit, semi-barter economy had a certain positive economic effect on Korsakov, though it inevitably contributed to organized crime.
Among other large economic units in Korsakov was a factory, which produced carton boxes—Fabrika Gofrirovannoy Tary. The factory operated on run-down equipment, probably left over from the Japanese times, and was visible to anyone in Korsakov, as it featured a tall chimney. Gennady Zlivko, formerly a mayor of the town, was once a director of this factory. It has long since gone bankrupt, and its tall chimney, no longer emitting black smoke, is the only thing that reminds one of the earlier years of Korsakov's economy.
Korsakov is also the closest town to the huge LNG plant, constructed within the framework of the Sakhalin-2 project.
Curiously, at the early stage of settlement (late 1890s), men in Korsakovsky outnumbered women almost by a factor of ten. In 1897, for example, 1510 males and 192 females lived in the town. This disbalance is explained by the fact that the majority of Korsakov's inhabitants were prisoners and prison-keepers—in both categories males predominated. The district of Korsakovsky (in 1897 covering 66762 verst) was home to 4659 males and 2194 females—a much better proportion (fort excluding).
The town's population stood at its highest (45 thousand) in the late 1980s, whereupon it experienced significant decline as inhabitants fled economic downturn by moving to neighboring Yuzhno-Sakhalinsk or to continental Russia. Evidently, Korsakov's population remains in decline, although no longer as sharp as in the 1990s.
The demographic make-up is primarily ethnic Russian with a large ethnic Korean minority.
Korsakov is the 2016 bandy champions of Sakhalin.
Amenities include a fairly run-down and expensive hotel ("Alfa") next to the former park. The beach is easily accessible by car (Okhotsk, about 1 hour and Prigorodnoye, about 30 minutes). Formerly well kept beach at Vtoraya Pad has now deteriorated into a messy junkyard.
Winter sights include skating at the city stadium and excellent cross-country skiing past the former sea weed plant (Na Agarike). No facilities exist for downhill skiing.
The town features a museum with an exhibit describing the local frontier history, and the Japanese possession of the city (1905–1945). Local market on the Sovetskaya Street offers great strawberries in the summer, and nicely prepared Korean delicacies (kimchi and the local hit, the paporotnik, all year around).
Foreign tourists are now able to visit the town without visa for 72 hours.
The town has its executive (the mayor's office or "municipal administration", and its legislature (Duma). In practice, the Duma exercises fairly limited influence over the executive.
List of mayors:
Korsakov is located about 30 kilometers (19 mi) from the Yuzhno-Sakhalinsk Airport. Regular bus and minibus services connect Korsakov with the capital city of Yuzhno-Sakhalinsk, though not with the airport. A passenger ferry service between Korsakov and Wakkanai, Hokkaidō, Japan, across the Aniva Gulf, was re-established in 2016 and is in operation between June and September of each year. The passenger ferry service is operated by the Commonwealth of Dominica flagged vessel Penguin 33, which is High-speed craft
The Japan National Rail passenger ferry service previously operated a service from Wakkanai, called "Chihaku-Renrakusen (Chihaku Ferry Service)" from 1923–1945, which was linked to Japan's national rail network and to Yuzhno-Sakhalinsk (then called Toyohara). The old narrow-gauge Japanese railroad still runs along the scenic coastline, with sporadic rail service.
There are several bus lines servicing the urban area and a number of villages in the proximity.