"In Jilin and Inner Mongolia, a marijuana field that is the largest on record since the establishment of the country was discovered," the China News Service reported, referring to the Communist Party's takeover in 1949.
The news agency gave no details about the size of the field nor did it say what authorities did in response to its discovery.
The nationwide satellite survey also revealed dozens of illegal cross-border tracks along the China-North Korea border and along the border of the western region of Xinjiang, where authorities are grappling with unrest.
Xinjiang borders Pakistan, Afghanistan and countries in ex-Soviet Central Asia but the news service did not say on which particular part of the border the tracks were found.
The government says Muslim separatists in Xinjiang have received training and inspiration from militants in neighboring countries such as Pakistan and Afghanistan.
As well as the marijuana field, the satellite survey found opium poppy fields in parts of Heilongjiang and Hebei provinces, and Inner Mongolia, the news agency said.
"These results provided important information support for enforcement by the Ministry of Public Security," it said.
REUTERS