The Department of Mineral Resources started geological mapping work since 1933, when it was merged with the Department of Lands as "the Royal Department of Lands and Mines. Six years later the first geological map of Thailand was published in black and white at the scale of 1:2,000,000 in 1939. In 1951, the Royal Department of Mines in corroboration with the US Geological Survey published the report entitled "Geologic Reconnaissance of the Mineral Deposits of Thailand as Memoir Geological No.1. This report includes the first reconnaissance geological map of Thailand at the scale of 1:2,500,000.
Presently, geological maps in printed and digital formats covering the whole area of the country are available in several scales, i.e., 1:2,500,000 1:1,000,000 1:250,000 and 1:50,000. Other types of maps such as area approach provincial maps, and line approach such as carbonate maps and Quaternary maps are also provided for the publics.
Geological survey and research have generated a huge number of geoscientific information, which enabled the DMR to set up the National Geological Standard and Lexicon of Stratigraphic names of Thailand and to revise the existing maps to satisfy the needs of the users.