The Pakchan River is an actual river which runs south to southwesterly from its source in the mountains in Lower Burma. For most of its course, it forms the border between Burma and Thailand along the Kra Isthmus. The river, also known as the Kraburi River in Thailand broadens into a wide estuary at Victoria Point (also known as Kawthuang). Across the estuary is the Thai town of Ranong.
In Biggles Delivers the Goods, Major Marling's estate at Shansie lies 50 miles up the river from Victoria Point, presumably on the Burmese side. This area is still very remote on the Burmese side. On the Thai side however, a road runs north from Ranong to reach the town of Kra Buri which stands today approximately opposite where in the book Shansie is supposed to be. This road is a popular route for tourists traversing the Kra isthmus of Southern Thailand from Ranong/Phuket in the west to Chumphorn in the east.