We present our simulation and experimental results on high-frequency properties of permalloy (Py) nanowire arrays. The planar Py nanowires are 10 μm long, 100 nm thick with widths of ~ 240 nm, and ~ 500 nm (layout dimension). The distance between adjacent Py nanowires is ~ 100 nm. OOMMF simulations indicate that single domain structures exist in these nanowires with ferromagnetic resonance frequencies (FMR) around 10 GHz. Coupling effects are negligible. The Oersted field of an external DC current reduces the FMR frequencies. The obtained Py properties can be used to simulate RF inductors to evaluate the application potentials of Py nanowire arrays in RF devices.