The term is historical and is not used today, but it's so colorful that it might be revived, at least as a business name.
29 April 1928, New York (NY) Times, pg. BR2:
Perhaps the best chapter of Mr. Asbury's book (The Gangs of New York - ed.) is that entitled "When New York Was Really Wicked." Its superior excellence derives from the fact that it is not wholly compounded of gangsters and their doings. It chronicles the growth of Satan's Circus, that area between Twenty-fourth and Forty-second Streets bounded by Fifth and Seventh Avenues. This section was the original Tenderloin, so christened by Inspector Alexander S. Williams, who enunciated the famous 'There is more law in the end of a policeman's nightstick than in a decision of the Supreme Court." Williams had fed on "chuck steak" for a long time in outlying districts; when he was transferred to Satan's Circus he was pleased that he was going to get a little of the "tenderloin."
Memoirs of a Murder Man
by Arthur A. Carey, late deputy in charge of the Homicide bureau, New York City Police Department, in collaboration with Howard McLellan
Garden City, NY: Doubleday, Doran and Company
And these detectives were forever going to or coming from the Burnt Rag, Stan's Circus, Hell's Kitchen, Cockran's Roost, McGuirk's Suicide Hall, the Bucket of Blood, Billy McGlory's place, the Slide, and other notorious rendezvous where a man was supposed to take his (Pg.8 - ed.) life in his hands when he entered. It gave these men a glamor which uniformed men never had.
New York City Guide:
a comprehensive guide to the five boroughs of the metropolis -- Manhattan, Brooklyn, the Bronx, Queens, and Richmond
By Federal Writers' Project
New York, NY: Random House
In the 1880's and 1890's the area between Twenty-fourth and Fortieth Streets, from Fifth to Seventh Avenue, was notorious as the wickedest and gayest spot in the city. Reformers of the day referred to it as "Satan's Circus."