This list was compiled from a quick overview of《南圻六省地輿誌》and as such, there may be more characters that I have missed and need to be included in the font.
Roughly, but not exactly, in the order that the characters appear (edit: added page numbers from 識典古籍. Only a few pronunciations are known):
- 哋 and 𠫵 (p.9) 哋 appears again on p.12 (readings unknown, implied for all future characters unless specified)
- 𤃉 (p.18) can be unified with 瀝?
- 𣿘 (p.23)
- 𡸀?(p.25) could also be 峒 which is included in the font
- 墥 (p.38, 44, 45, 49, 77) đồng? (Đồng Tháp = 墥塔)
- 厯 (p.48) alt form of 歷
- ⿱水巳 (p.50)
- 𪨸 (p.23)
- ⿲亻𠀋丶 (p.23) unifiable with 仗?
- (p.52, 65) unifiable with 汊?
- 湤 (p.51)
- 𪩂 and ⿱山師 (untraceable)
- ⿰氵的 (p.78)
- 𥩪 (.42) mistake for 站?
- ⿰目⿱巛竜 (p.51)
- ⿱卯壯 (p.68) cf. 𫧾 trứng which fits Chinese gloss 蛋
- 𭛒 (p.82)
- 𪤡 (p.84)
- 𫻪 (p.84, 85, 86) may be equivalent to later 忒 on p.104, 105
- 鉓 (p.86)
- ⿰木歌 (p.86) possibly cà as in Cà Mau? Chinese Wikipedia says it's also attested as 哥毛、歌毛、歌牟 etc
- ⿱艹𡘃 and ⿸厂曹 (p.86)
- 𤦛 (p.101) variant of 瑁
- ⿱舉門 (p.105)
- ⿰羊厷 (p.62)
- 樒 (p.63)
- unknown IDS (5th character) (p.95)
- (p.100)
- 𨔛 (p.103)
- ⿰九分 (p.106)
- ⿰米叁 (p.106) unifiable with 糁?
The following characters were found after the initial issue:
- ⿱臼會 (p.51)
- ⿱日男 (p.72)
- 嵓 (variant of 巖) and ⿰山𢧜 (p.72)

This list was compiled from a quick overview of《南圻六省地輿誌》and as such, there may be more characters that I have missed and need to be included in the font.
Roughly, but not exactly, in the order that the characters appear (edit: added page numbers from 識典古籍. Only a few pronunciations are known):
The following characters were found after the initial issue: