Nanopores with lateral dimensions as small as 33 nm have been fabricated by nuclear track etching in 5 mu m thick, single crystal mica wafers. The nanopores have a diamond shape with their axes aligned with the crystal axes of mica as a result of anisotropic etching. Nickel nanowire arrays with a constant volume fraction have been fabricated by electrodeposition into the nanopores. The magnetic properties of the nickel nanowire arrays in the mica templates are reported.