Broadband spin-wave spectroscopy is performed on two arrays of long 300-nm-wide Ni(20)Fe(80) wires which exhibit two different edge-to-edge separations a of 700 and 200 nm. When the in-plane field (H) over right arrow is applied a few degrees off from the hard axis direction, an intermediate field regime is found where the central region and the edges of a wire are magnetized in different directions. Here, resonances are pronounced and reflect spin waves confined on the sub-100 nm scale within a wire. For small a, the confinement effect is found to occur over a broad regime of H. These results are relevant for high-density integration of magnonic waveguides. (c) 2009 American Institute of Physics. {[}DOI: 10.1063/1.3056151]