Rhinos will face Warrington at Bolton Wanderers’ University of Bolton Stadium - which has an official capacity of 28,723 - on Sunday (2.45pm), after Catalans Dragons take on St Helens (12.30pm).
It is the first time both semi-finals have been staged at one venue on the same day.
Rugby Football League chief executive Ralph Rimmer said: “The Ladbrokes Challenge Cup is the most prestigious competition in rugby league and holding two semi-finals in one stadium is another historic moment in its legacy.
“It’s fantastic that the two fixtures will be played in front of a full house at the University of Bolton Stadium.
“I am certain that the capacity crowd will create an incredible atmosphere at Bolton and I look forward to watching two extraordinary games between four top sides.”