Map of Foreign Countries

China is unsurpassed by the various nations of the East. The Mekong Mekong (Méi gōng): the primary river of Southeast Asia is the most significant waterway in Annam Annam (Ān nán): an historical name for Vietnam.
The Mekong River seems to refer to the Fuliang River original: 富良江; historically this name referred to the Red River in the north, but the author here conflates it with the Mekong or suggests a shared identity; its upper reaches are the Lihua River original: 黎花江 in Yunnan.
It also originates in Yunnan, flows south through Ba-er-men original: 巴爾門; likely a phonetic transcription of a local landmark or city, possibly related to Phnom Penh or a coastal entrance and empties into the sea.
Flowing through Annam into the sea.
Sailing upstream from the river mouth for about twenty-odd days, large ships can hoist their sails and travel directly. The local products of the three regions referring to the three traditional divisions of Vietnam: Tonkin, Cochin-China, and the former Champa territories include cotton, grains, wood oils, patterned woods, white sugar, pepper, rattan, bamboo, gamboge Gamboge (Dǎn huáng): a bright yellow resin produced from trees, used as a pigment and in medicine, betel nut, bird's nest, sea cucumber, and ivory.
Original text

The Kingdom of Annam is bordered by the sea to the east and south, by Siam Siam (Xiān luó): Thailand to the west, and by Guangxi, China, to the north. It uses Hudi original: 虎地 (Hǔ dì), a phonetic rendering of the capital city of Huế as the national capital and governs twenty-one tribes.
The names of the tribes in the original text are all in foreign tongues and have been omitted here; the administrative details of Annam's commanderies and counties are described in full in earlier official histories.
Re-compiled
This section was missing from the original and has now been added.

The Collected Complete Maps of the World's Geography Wanguo Dili Quantu Ji: a significant 19th-century geographical text influenced by Western mapping states: The King of Annam occupies Tonkin Tonkin (Dōng jīng): Northern Vietnam and has seized the vast territory of the Kingdom of Champa Champa (Zhàn chéng): an ancient seafaring kingdom in central and southern Vietnam absorbed by Annam.