A cable backplane system includes cable backplanes each including a tray configured to be coupled to a chassis and a plurality of cable connector assemblies mounted to the tray. The tray has a plate extending between a front and a rear with mounting locations receiving corresponding cable connector assemblies. The trays are oriented parallel to each other with front openings between the fronts of the plates and rear openings between the rears of the plates. Each cable connector assembly has a housing holding contacts terminated to corresponding cables. Each cable connector assembly has a holder mounted to the corresponding mounting location of the plate. The holder is mounted to the plate and removable from the plate through the rear opening at the rear of the plate.