Ideal nanowire interconnects for nanoelectronics will be refractory, covalently bonded, and highly conductive, irrespective of crystallographic orientation. Theoretical studies suggest that boron nanotubes should be stable and exhibit higher electrical conductivities than those of carbon nanotubes. We describe CVD growth of elemental boron nanowires, which are found to be dense nanowhiskers rather than nanotubes. Conductivity measurements establish that they are semiconducting, with electrical properties consistent with those of elemental boron. High conductivities should be achievable through doping.