An outbreak of 77 confirmed tornadoes occurred in seven U.S. states; it became the largest November tornado outbreak in Illinois and Indiana.

On November 17, 2013, the deadliest and costliest November tornado outbreak in Illinois history took shape, becoming the fourth-largest for the state overall. With more than 30 tornadoes in Indiana, it was that state's largest tornado outbreak for the month of November, and the second largest outbreak recorded in Indiana. Associated with a strong trough in the upper levels of the atmosphere, the event resulted in 77 tornadoes tracking across regions of the Midwest United States and Ohio River Valley, impacting seven states. Severe weather during the tornado outbreak caused over 100 injuries and eleven fatalities, of which eight were tornado related. Two tornadoes—both in Illinois and rated EF4 on the Enhanced Fujita scale—were the strongest documented during the outbreak and combined for five deaths. In addition to tornadoes, the system associated with the outbreak produced sizeable hail peaking at 4.00 in (10.2 cm) in diameter in Bloomington, Illinois, as well as damaging winds estimated as strong as 100 mph (160 km/h) in three locations.

Illinois is a state in the Midwestern region of the United States. It borders Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash and Ohio rivers to its south. Of the fifty U.S. states, Illinois has the fifth-largest gross domestic product (GDP), the sixth-largest population, and the 25th-most land area. Its capital city is Springfield in the center of the state, and the state's largest city is Chicago in the northeast.

Indiana is a state in the Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the south and southeast, and the Wabash River and Illinois to the west. Nicknamed "the Hoosier State", Indiana is the 38th-largest by area and the 17th-most populous of the 50 states. Its capital and largest city is Indianapolis. Indiana was admitted to the Union as the 19th state on December 11, 1816.