In botany, he is remembered as the author of the 1860 Flora Fennica, the first scientific text written in Finnish rather than in Latin.

As the university was destroyed in the fire, it was moved to Helsinki, the newly established administrative center of the Grand Duchy of Finland.

[2] Lönnrot went on extended leaves of absence from his doctor's office; he toured the countryside of Finland, Sapmi (Lapland), and nearby portions of Russian Karelia.

Lönnrot was recognised for his part in preserving Finland's oral traditions by appointment to the Chair of Finnish Literature at the University of Helsinki in 1853.

[10] His vast knowledge of traditional Finnish poetry made him a definite authority in Finland and many of his inventions have stuck.

Examples from linguistics and medicine include kielioppi (grammar), kirjallisuus (literature), laskimo (vein) and valtimo (artery).

The Kalevala, the Finnish national epic that Lönnrot compiled, was among the inspirations for J. R. R. Tolkien's the Silmarillion and The Lord of the Rings.