The head of the Sakhalin Region museum's cultural heritage department, Igor Samarin, said the findings dated from the Lower Paleolithic period up to World War II, and include ancient settlements, military camps, battle sites, and artifacts of Russian and Japanese origin.
"Archaeology on Sakhalin has never seen field work on such a scale," he said.
Between 2004 and 2007 archaeologists carried out excavation works on the 3,500 square meter area of the pipeline route, and made around 30,000 discoveries.
The pipeline is being built for the Sakhalin II project, controlled by Russia's state natural gas giant Gazprom.
The findings included a Japanese fireproof pavilion used to keep a portrait of the emperor and his decrees. Archaeologists also discovered items belonging to the Soviet soldiers who fought in World War II.
The Soviet Union annexed the southern part of Sakhalin from Japan after WWII.
