The purpose of this essay is to examine the scientific relations between Sweden and America, later USA, through the letter correspondence between Nils Collin and his fellow “scientists” in Sweden and America between 1770–1830. By examining the letters though three different theoretical lenses: Scientific persona, gift exchange and the geography of knowledge with the concepts of centers and peripheries, the inquiry shows us how the scientific relations between the two countries developed and changed during the investigated time period, thus adapting themselves to the political developments that created an international scientific arena instead of the earlier nation neutrality. The letter correspondence reflects the increase in communication between Swedish scientists and American scientists as well as between Swedish institutions such as The Royal Swedish Academy of Sciences and The American Philosophical Society with Nils Collin as their main go-between. The letters indicate that Nils Collin’s role within the communication network changed with time and that he became an enabler of knowledge circulation between Sweden and the US though his position and many contacts. Lastly, by examining the letters, we can see how the increased communication as well as Nils Collin’s changing role plays part in the American scientific and national development that ultimately changed the earlier ideas of centers and peripheries of knowledge.