The electronic and magnetic properties of bilayer graphene (BLG) depend on the stacking order between the two layers. We introduce a new conceptual structure of "slip corona" on BLG, which is a transition region between A-A stacking close to a nanopore composed of bilayer edges (BLEs) and A-B stacking far away. For an extremely small nanopore (diameter D(pore) < ∼5 nm), both atomistic simulations and a continuum model reach consistent descriptions on the shape and size of this "corona" (diameter ∼50 nm), which is much larger than the width of the typical dislocation core (∼1 nm) in 3D metals or the nanopore itself, due to the weak van der Waals interactions and low interlayer shear resistance between two adjacent layers of graphene. The continuum model also suggests that the width of this "corona" from the BLE to the A-B stacking area would increase as D(pore) increases and converge to ∼40 nm when D(pore) is more than ∼80 nm. This large stacking transition region provides a new avenue for tailoring BLG properties.