This list of birds of Illinois includes species documented in the U.S. state of Illinois and accepted by the Illinois Ornithological Records Committee (IORC). As of August 2022, there are 453 species and two species pairs included in the official list. Of them, 91 are classed as accidental, 38 are classed as casual, nine have been introduced to North America, three are extinct. The native populations of five species have been extirpated though some of them have been reintroduced. The following codes are used to designate some species: