Asymmetric microporous membranes with localized asymmetries, devices including the membranes, and methods of making and using the membranes, are disclosed. The asymmetric microporous membranes have a first surface and a second surface and an interior bulk defined by the first and second surfaces, wherein the first surface has at least a first region and a second region, the first region having a first porosity comprising a first mean pore size, and the second region having a second porosity comprising a second mean pore size, wherein the ratio of first mean pore size to the second mean pore size is at least about 5:1.