Þorvaldur Thoroddsen (1855-1921) was an Icelandic geologist and geographer. Þorvaldur’s interest in geology is said to have been fuelled when he accompanied the geologist Johannes Frederik Johnstrup to Iceland in 1876, as a guide. Apart from making the first geographical map of Iceland, Þorvaldur write about volcanos, weather, and other subjects. He was among the most respected scholars of his time in Iceland.