Is there any way I can reclaim this space and still safely support the front steps?
Couple possibilities I can think of (hard to tell without looking at a floor plan):


Floor was built over a larger area and then covered over.
Landing or base of the stairs was moved, possibly during early construction.
Floor or landing was intentionally extended to provide a shelf for storage.
Joists are continuing to a load bearing structure (wall of the house).


Without being physically there, or reviewing a building plan, it's difficult to say how you can move/remove this structure.