Elias Lönnrot (April 9, 1802 - March 19, 1884) was a Finland-Swedish philologist and collector of traditional Finnish oral poetry . He is best known for composing the Kalevala, the Finnish national epic.

Lönnrot was born in Sammatti, Finland. He studied medicine at the University of Turku (Åbo in Swedish). Unfortunately the year he joined was the year of the Great Fire of Turku, burning down half the town - and the University. Lönnrot (and much of the rest of the University) moved to Helsinki, where he graduated in 1832. He got a job as district doctor of Kajaani (about in the middle of Finland) during a time of famine in the district. The famine had prompted the previous doctor to resign, making it possible for a very young doctor to get such a position. Several consecutive years of crop failure resulted in enormous losses of population and livestock; Lönnrot wrote letters to the State departments, asking for food, not medicines. He was the sole doctor for the about 4000 people of his district, at a time where doctors were rare and very expensive, and where people did not buy medicines from equally rare and expensive pharmacies, but rather trusted to their village healers and locally available remedies.

His true passion lay in his native Finnish language. He began writing about the early Finnish language in 1827 and began collecting folk tales from the rural people about that time.

Lönnrot went on extended leaves of absence from his doctor's office; he toured the countryside of Finland, Sapmi (Lapland), and nearby portions of Russia to support his collecting efforts. This led to a series of books: Kantele, 1829--1831 (the kantele is a Finnish traditional instrument); Kalevala, 1835--1836 (possibly Land of Heroes; better known as the "old" Kalevala); Kanteletar, 1840 (the Kantele Maiden); Sananlaskuja, 1842 (Proverbs); an expanded second edition of Kalevala, 1849 (the "new" Kalevala); and Finske-Svenskt lexikon, 1866--1880 (Finnish-Swedish Dictionary).

Lönnrot was recognised for his part in preserving Finland's oral traditions by appointment as the Chair of Finnish Literature at the University of Helsinki. He died on March 19, 1884 in Sammatti, in the province of Nylandia.

Botanists remember him for writing the first Finnish-language Flora Fennica - Suomen Kasvisto in 1860; in its day it was famed throughout Scandinavia, as it was among the very first common-language scientific texts. The second, expanded version was co-authored by Th. Saelan and published in 1866; this version is online here: ibiblio (in Finnish). The Flora Fennica would be comparatively insignificant were it not for the fact that Lönnrot, besides verses for the Kalevala, also collected uses of plants in his travels. His Flora Fennica includes many notes on plant uses in between descriptions of flower and leaf.

The Finnish graphic artist Erik Bruun used Lönnrot as a motive for the 500 markka banknote in his banknote series.

As a botanist he was well-respected, and in the standard botanical author abbreviation Lönnrot is applied to species he described.