Hawkworld is a pivotally important series in Hawkman's notoriously confusing continuity. Following the Crisis on Infinite Earths in 1986, a large number of DC's major characters were given rebooted origins. Hawkworld in 1989 was originally intended to serve this purpose for Hawkman, but it was so popular that DC decided to retroactively make it set in the present day instead of in the past. It was directly continued in the Hawkworld ongoing series. This created a problem as Katar Hol was now coming to Earth for the first time, but stories had been referencing his past involvement with the Justice League for three years between the two series'. It was explained that the Hawkman who served with the early Justice League was actually a separate character, and we all agreed to never speak of this again.
The name "Hawkworld" can also apply to Hawkman's home planet Thanagar.