Illinois Open Championship

{{Short description|State golf championship of Illinois}}

{{use mdy dates|date=August 2021}}

{{infobox golf tournament

| name = Illinois Open Championship

| image =

| caption =

| location = varies – Flossmoor, Illinois in 2024

| course = varies – Flossmoor CC in 2024

| establishment = 1950

| par = 72 (in 2024)

| yardage = {{convert|6933|yd|m}} (in 2023)

| org = Illinois PGA

| tour =

| format = 54-hole stroke play

| purse =

| month_played = August

| final_year =

| aggregate =

| to-par =

| current_champion = Charlie Nikitas

| final_champion =

}}

The Illinois Open Championship is a golf tournament that is administered by the Illinois PGA (Professional Golfers' Association). The state championship of golf is a 54-hole championship over three days to determine the finest player in the state of Illinois. The tournament is open to professionals and amateurs with a handicap of 10 or less who reside within the state of Illinois.

In 2015, for the first time in the history of the Illinois Open, the Illinois PGA changed the format of the event having it contested at two facilities for the first and second rounds.

The final championship field size after qualifying events increased from 156 to 258 players. The number of competitors making the cut also increased to the top 70 and ties from the top 50 and ties. Qualifying events conducted throughout the month of June finalize the championship field to the top 258 players.