Codex canadensis is a handwritten and hand-drawn document from c. 1700 that depicts the wildlife and native peoples of Canada. It contains 180 drawings of First Nations' people, plants, mammals, birds and fish of the New World. Although the manuscript was neither signed nor dated, scholars believe its most likely author was Louis Nicolas, a French Jesuit. It is currently kept at the Gilcrease Museum, in Tulsa, Oklahoma.

When a facsimile of the Codex was produced in 1934, a foreword by Baron Marc de Villiers attributed the original work to Bécart de Granville. Scholars have more recently discovered that the author was probably Nicolas. The Histoire Naturelle des Indes Occidentales, a document held at the Bibliothèque nationale de France in Paris, is speculated to have also been written by Nicolas and provides an in depth description of the animals, fish and plants of Canada, which are all depicted in the Codex Canadensis.

The author of the Histoire Naturelle also mentions that the descriptions of his observations are accompanied by illustrations: French: toute sorte de bons poissons, qu'on ne voit pas dans nôtre Europe, dont je vous donneray a la fin de mon Histoire naturelle, les noms, les figures, et les portraits. The author of the latter document signed his work M.L.N.P, which recalls the initials of the Grammaire Algonquine 's author, Louis Nicolas. Furthermore, in the Grammaire 's preface, the author specifies that he has placed at the end of his book an extra section on the history of the country: "On a mis à la fin de cette grammaire un petit supplément de l'histoire du pays". The Codex Canadensis and Histoire Naturelle des Indes Occidentales could easily be the supplement Louis Nicolas refers too. Indeed, the similarities between the Codex Canadensis, the Histoire Naturelle and the Grammaire Algonquine make it reasonable to believe that all three documents were written by the same man, Louis Nicolas, Priest and Missionary.

Louis Nicolas was born in 1634 in Ardèche, France. He joined the Jesuits at age 20. In 1664, he arrived in New France, where his order was sent to convert the Aboriginal peoples. As he travelled, his interest in Aboriginal languages and culture increased. Nonetheless, he did not always behave accordingly towards the native peoples. He could be "quick-tempered and rather vain". In 1675, he returned to France.

Apart from its depictions of plants, animals, and native peoples, the Codex Canadensis also includes two maps. The inside front cover of the tome contains a map of the Mississippi River and its environs, while the inside back cover contains a map of northeastern North America, including territories such as New France and Acadia, as well as New England, New York, Newfoundland and the region of the Great Lakes. Hence, both of the maps depict French colonial spaces in North America.

Both maps contain quite a large amount of detail when it comes to labeling settlements, particularly in coastal areas and along rivers. This is consistent with European cartography of the Americas in the early modern period. The detailed depictions of coastal and fluvial settlements was important due to the importance ships had in the transportation systems of the time, particularly in the New World. Furthermore, the mapping of settlements as can be seen in the Codex Canadensis, and cartography in general, played an important role in the imperial endeavours of European powers in this period. In that sense, the maps in the Codex can be seen as part of the wider context of cartography as a colonial tool, a way of asserting control over certain spaces.

The presentation of Native (Indian) communities in the Codex Canadensis is a veritable compendium of different aspects of indigenous life. The sketches represent many different communities, from Algonquin to Iroquois to Outawaks and so on, and document the varying lifestyle between the communities. One page details the different types of canoe dependent on community, and there is another page similarly devoted to different types of cabins. The inclusion of mythology through the various representations of Natives and their interaction with the sun or moon additionally adds to the full picture that composed Native life. This ethnographic pictorial study of these communities provides a more literal depiction of these communities as other similar studies of the time, such as that of DuCreux, were less observant of the ornamentation of bodies such as tattoos, which Louis Nicolas takes much care to draw in detail.

The captions describe the native peoples as sauvages or barbares, implying the subordination of these communities to the arrival of Europeans in the New World. This is subordination, not racial degeneration, as contemporary French ideas of the time were formed about the unity of all humankind; therefore the Native societies were believed to be less civilised than their French contemporaries, seen with their use of language. The equation of Natives with the New World's flora and fauna in the Codex Canadensis further shows this subordination.