1781: The Ganges from teh Calligongato its confluence with the Megna or Burrampooter: and the Megna from thence to the head of the Luckla River.

1781 — “The Ganges from the Calligongato to its Confluence with the Megna… and the Megna from Thence to the Head of the Luckla River”

This map, made circa 1781 (often attributed to James Rennell), charts the Ganges River from its mouth near Calligongato (Calligonga) to the point where it joins the Meghna (also called the Burrampooter), and then follows the Meghna upstream to the head of the Luckla (Luckia) River. 

It offers valuable insight into 18th-century river navigation, showing river courses, tributaries, and the hydrological landscape of the Bengal delta region. The map is part of a Bengal atlas collection and reflects the colonial and cartographic interests in understanding and controlling the waterways of Bengal.

Calligonga River: This was a name used on old maps, such as those from 1786, to refer to the Ganges River or a part of its delta in the Bengal region, notes oldmapsonline.org.

Map of India with Ganges River Insets features in Thomson's New General Atlas (1817)

Thomson's New General Atlas" was a large-scale, early 19th-century atlas published by Scottish cartographer John Thomson in Edinburgh, first in 1817. It was one of the most ambitious British atlases of its time, featuring detailed and decorative maps of the world, notable for their clarity and accuracy. Though it was a commercial success, Thomson later went bankrupt despite the atlas's popularity. 

This 1817 map depicts the entire Indian subcontinent, from Lahore to Sri Lanka, with cities, rivers, mountains, and deserts. The right side features detailed insets of the Ganges River, including a cross-section, its dry-season course, and inland navigation routes from the Bay of Bengal to Allahabad.

The map draws on surveys by James Rennell, the first Surveyor General of Bengal (c. 1781), whose river charts were foundational for later maps. Rennell’s work was incorporated into Laurie & Whittle’s maps in the 1790s and later into Thomson’s atlas, which updated place names and administrative boundaries while preserving the essential hydrology of Bengal.

John Thomson (1777–c.1841) was a leading Scottish cartographer known for prioritizing accuracy and clarity over decorative elements. His New General Atlas (1817–1821) is celebrated for its impressive scale, vivid hand coloring, and precise detail, making this map one of the finest early 19th-century representations of India and its rivers.

Publication: First published in Edinburgh in 1817 by John Thomson & Co., with distribution partners in London and Dublin. 

Content: It featured a series of finely engraved maps that illustrated both natural features and political divisions on a global scale. 

Features: The atlas included extensive topographical and historical notes, as well as a consulting index. It was known for its impressive size and quality of engraving. 

Legacy: It was a major work in Scottish cartography and is still highly valued today for its early 19th-century geographical insights and elegant engraving.