In the Qing era Manchuria was originally governed separately from the
rest of China. Later on it was divided into three provinces
(Heilongjiang, Jilin/Kirin, Fengtian/Liaoning) with borders similar to
the current PRC borders. This 3-province division continues until the
Japanese invasion (didn't matter much anyway since the region was
effectively under warlord rule from 1916 - 1931). When the Japanese created Manchukuo it was divided into five, then 19 provinces. (
wiki link). During RoC era (post-1945) Manchuria was divided into 8 provinces (9 if you count Hsingan which is nowadays part of Inner Mongolia).
As for the Amur and Ussuri regions, used to be divided between Heilongjiang and Jilin.
Edited by Voskhod - 11-Dec-2008 at 10:56