Some embodiments of the present disclosure are directed to endoluminal prostheses having one or more reinforced fenestrations therein. The one or more reinforced fenestrations can have improved sealing capabilities with respect to branch grafts deployed within the fenestrations, improved tear resistance and expandability, and improved pull-out resistance for branch grafts. In some embodiments, the endoluminal prosthesis can have a main graft body defining a flow lumen therethrough, a first opening passing through a wall of the main graft body, and a first support member supported by the main graft body and overlapping an edge of the first opening, the first support member being configured to at least increase the tear resistance of the main graft body adjacent to the first opening. The support member can be stitched or otherwise attached to the main graft adjacent to the fenestration.