Acoustic streaming relies upon viscous attenuation of a propagating acoustic wave in a fluid to generate momentum flux and fluid flow. It is a nonlinear second-order phenomenon that generally produces rapid (∼10 cm/s) fluid flow but only against weak (∼10 kPa) pressure gradients. Here we describe a new form of acoustic streaming—acoustogeometric streaming—that is still nonlinear but relies on the interaction between the acoustic wave and the bounds of the fluid passage. If the boundaries oscillate with an amplitude that is significant in comparison to the width of the fluid passage, similarly rapid fluid flows may be generated even against very large (>1MPa) pressure gradients. This is used to propel fluids at 6 mm/s in 20–150 μm wide, 100 nm tall nanoslit geometries and to transport, split, combine, and mix ∼100 fl droplets of fluid. In this presentation, we will also show what happens when the nanoslit height is reduced below 10 nm, and demonstrate specific examples with some simple analysis that explains the various phenomena, closed by some explanation of the broader potential benefit of this approach.