An equation of motion is derived which describes finite‐wavelength (i.e., axial wavelength ∼ plasma radius) oscillations of a Vlasov‐ion, fluid‐electron plasma in a diffuse, near‐&Vthgr; pinch geometry. The equations include simultaneous geometric and ion kinetic effects. For a screw‐pinch geometry, and with isothermal electrons, these equations are shown to be equivalent to the guiding‐center equations. Boundary conditions and a closed‐form solution for the sharp‐profile case are discussed.