We present fabrication and measurements of gated suspended low-dimensional electron systems. The core component of the device is a low-dimensional electron gas embedded in a free-standing beam processed from a GaAs/AlGaAs heterostructure. The dimensionality of the electronic system is fully controlled by a number of gating electrodes on the suspended membranes. Operation in the quantum Hall regime, in the one-dimensional case, and as zero-dimensional quantum dots is demonstrated. The resulting devices can be applied as ultrasensitive bolometers and as nanoelectromechanical circuits that reach the ultimate limits of displacement detection. (C) 2003 American Institute of Physics.