[2] The Treaty of Portsmouth in 1905, which brought an end to the Russo-Japanese War of 1904–1905, awarded the southern half of the Sakhalin Island to Japan.

Vladimirovka was renamed Toyohara (meaning "bountiful plain"), and was the prefect capital of the Japanese Karafuto Prefecture.

Due to significant investment from oil companies like ExxonMobil and Shell, Yuzhno-Sakhalinsk has experienced substantial economic growth.

Although this growth has primarily occurred in the northern part of the island, both companies maintain headquarters and residential complexes in the city of Yuzhno-Sakhalinsk itself.

The demand for natural resources by the Japanese, Chinese, and South Koreans has ensured continued prosperity in the foreseeable future for the entire island.

Due to restrictions, foreigners wishing to leave Yuzhno-Sakhalinsk in order to travel to any other part of the Sakhalin Oblast and its internal and territorial waters are required to seek permission from the Federal Security Service (FSB) and the Border Guard.

Maritime influences can be seen in that precipitation is much higher than in interior Russia and that summers are distinctly cooler than in Khabarovsk or Irkutsk, while winters are much milder.

Considering its southerly maritime position winters are very cold, albeit warmer than expected for surrounding inland areas affected by the Siberian High.

Yuzhno-Sakhalinsk is relatively sunny compared to Hokkaido locations, but gloomy by the lower latitudes of the Russian Far East's standards.