Haley's Circus was a traveling circus.
Owned and run by Mr. Haley, the Circus was renowned for its trapeze act, the Flying Graysons. Despite the death of John and Mary Grayson in a horrible accident, the circus was able to keep going, eventually acquiring new trapeze artists.
At one point, the circus also acquired a new clown, who briefly used the circus's animals, including Peaches the gorilla and bears Polly and Dolly, in a string of robberies before being apprehended by Batman and Nightwing.
What happened to Haley's Circus following those events is unknown.