We analyze subwavelength cylindrical holes in an optically thick metallic film with the metal described by a plasmonic model. We emphasize that such holes always support propagating modes near the surface plasmon frequency, regardless of how small the holes are. Based on this analysis, we design both single holes and hole arrays in which propagating modes play a dominant role in the transport properties of incident light. These structures exhibit a region of operation that to the best of our knowledge has not been probed yet experimentally, while featuring a high packing density and diffraction-less behavior. (c) 2005 American Vacuum Society.