There is no accepted or conclusive answer as to why Indiana is referred to as the Hoosier State. The first known reference to the word "hoosier" dates back to 1827 when it was used in a letter, states the Indiana Historical Society.
Another early mention of the word "hoosier" occurred when General John Tipton was approached with an offer from a businessman to name his own boat Hoosier State in exchange for business. Using hoosier became very common in the 1830s. Around this time period, a poem called "The Hoosier's Nest" became popular. Bartlett's Dictionary of Americanisms defined "hoosier" in 1848 simply as a nickname given to Indiana natives.