There is no river at 30 degrees north and 40 degrees east.
The Karun River
The river located at approximately 30 degrees north and 48 degrees east is the Karun River in Iran. It is the longest river in the country, flowing through the Khuzestan province and eventually draining into the Shatt al-Arab waterway. The Karun is significant for its role in irrigation and as a water source for the region.
30 degrees north and 150 degrees east is in the North Pacific, southeast of Tokyo, near where Godzilla was created.
The Himalayas are at 30 degrees north and 82 degrees east.
30 degrees north and 55 degrees east is in Iran.
Asia is at 30 degrees north and 105 degrees east.
30 degrees north and 138 degrees east is in the Pacific Ocean. The point is south of Japan and east of China.
30 degrees north and 59 degrees east is in southeastern Iran, about 115 miles east-southeast of Kerman. It is on the continent of Asia.
30 degrees north and 105 degrees each is in Sichuan Sheng, China, on the continent of Asia.
30 degrees north and 21 degrees east is in Libya, on the continent of Africa. It is southwest of Aidabiya.
It is the Persian Gulf, which is actually an arm of an ocean or sea rather than a river.
30 degrees north and 15 degrees east cross in Libya, on the continent of Africa. The point is northwest of Waddan and east of Ash Shwayrif.