The use of herbaria became important in the 18th century when linked to advancements of the field of botany as well as a general desire to know and describe the flora of different regions.  Like his predecessors and contemporaries, the Neuchâtel (Switzerland) botanist Jean-Frédéric Chaillet (1747-1839) inventoried and collected the plants he encountered and preserved them as dried specimens. While he devoted most of his life to the study of cryptogams, for which he was most recognized, he naturally began with the study of flowering. Self-taught and persevering, Chaillet established the most complete collection of plants in Neuchâtel, a region he botanized in for more than 40 years. After his death in 1839, a first sorting of his collection was undertaken before its integration in the local institution. Subsequently, after various moves, the entire collection was reconditioned at the end of the 20th century. Today, his flowering plant specimens can be found intercalated in the herbarium of the University of Neuchâtel (NEU). His specimens that were collected between 1788-1830 comprise more than 2,000 specimens and over 1,800 taxa. Moreover, a handwritten catalog of his herbarium containing a list of more than 3000 taxa, allows to evaluate the number of specimens between 3000-4000. The richness of the information present on the labels is quite exceptional for the time. The virtual reconstitution of the Chaillet herbarium, which includes many challenges, makes it possible to consult, complete and develop this collection as a scientific and historical heritage.