Beginning in the 19th century, there was migration from Ukraine to distant areas of the Russian Empire. According to the 1897 census, there were 223,000 ethnic Ukrainians in Siberia and 102,000 in Central Asia. An additional 1.6 million emigrated to the east in the ten years after the opening of the Trans-Siberian Railway in 1906. Far Eastern areas with an ethnic Ukrainian population became known as Green Ukraine.