A set of approximately 1,665 historical maps of South Asia produced by the Survey of India at a scale of 4 miles per inch (1:253,440). These maps cover the territory from Eastern Persia (Iran) through present day Afghanistan, Pakistan and India and on to Burma, and parts of Western China and Southeast Asia, and in general were produced during the first half of the 20th century. The file naming convention is to first give the number of the 4 degree x 4 degree block followed by the letter (A to P) of the sixteen 1 degree x 1 degree blocks in each 4 degree block eg. 38 D. This is followed by the name of a town or geographical area encompassed by the map, followed by the date of publication in parenthesis. If a map is reprinted without changes sometime after its initial publication, it is the date of initial publication that is used. An Index Map with the title "0 Topographical Index of Survey of India 253k and 126k Mar 2022" showing the sheet numbering system is provided as the first entry in the list of files. This index map can be downloaded to assist in selecting particular maps of interest to the viewer. The maps are then listed in numerical order by sheet number. More than one map will be shown for each geographic block when maps with different publication dates are available. The viewer may find it convenient to use the Search Function (Windows: Ctrl-F or Mac: Cmd-F) to open a search window and quickly navigate to a particular map of interest. A click on the "Preview" button will open a preview image, but it will be located at the very top of the file list. A click on the "Download" button will download the map file to the viewer's computer. The map scans are collected from many sources, and the quality of the scans as well as the underlying paper maps is uneven. Some scans are professionally done, while others are of poor quality. On the assumption that 'some map is better than no map,' we include the poor quality scans until a better copy can be obtained.