An in-plane accelerometer comprising: a base including a substantially planar mounting surface; an accelerometer mechanism formed in a doped silicon mechanism layer, the accelerometer mechanism including: substantially rigid first and second outside electrode structures (110, 112), the electrode structures having substantially parallel and mutually opposing pickoff electrode surfaces (114, 116) oriented substantially perpendicular to the planar mounting surface of the base and spaced apart along an input direction (y) parallel with the planar mounting surface of the base; and a proof mass suspended between the first and second outside electrode structures, wherein the proof mass is oriented substantially perpendicular to the planar mounting surface of the base, the proof mass comprising: substantially identical cantilevered beams (120, 122) that extend along the x-dimension, the cantilevered beams being configured to move along the input direction; and a central pendulum mount between the cantilevered beams, the cantilevered beams extending on either side of the pendulum mount, wherein the mechanism layer is shaped in the x and y dimensions with a fixed z dimension; first and second anchors that secure the first and second outside electrode structures, respectively, to the mounting surface of the base, wherein the first and second anchors each extend over a significant portion of an attachment area of the respective outside electrode structures; and an anchor that secures the pendulum mount to the base. a base including a substantially planar mounting surface; an accelerometer mechanism formed in a doped silicon mechanism layer, the accelerometer mechanism including: substantially rigid first and second outside electrode structures (110, 112), the electrode structures having substantially parallel and mutually opposing pickoff electrode surfaces (114, 116) oriented substantially perpendicular to the planar mounting surface of the base and spaced apart along an input direction (y) parallel with the planar mounting surface of the base; and a proof mass suspended between the first and second outside electrode structures, wherein the proof mass is oriented substantially perpendicular to the planar mounting surface of the base, the proof mass comprising: substantially identical cantilevered beams (120, 122) that extend along the x-dimension, the cantilevered beams being configured to move along the input direction; and a central pendulum mount between the cantilevered beams, the cantilevered beams extending on either side of the pendulum mount, wherein the mechanism layer is shaped in the x and y dimensions with a fixed z dimension; first and second anchors that secure the first and second outside electrode structures, respectively, to the mounting surface of the base, wherein the first and second anchors each extend over a significant portion of an attachment area of the respective outside electrode structures; and substantially rigid first and second outside electrode structures (110, 112), the electrode structures having substantially parallel and mutually opposing pickoff electrode surfaces (114, 116) oriented substantially perpendicular to the planar mounting surface of the base and spaced apart along an input direction (y) parallel with the planar mounting surface of the base; and a proof mass suspended between the first and second outside electrode structures, wherein the proof mass is oriented substantially perpendicular to the planar mounting surface of the base, the proof mass comprising: substantially identical cantilevered beams (120, 122) that extend along the x-dimension, the cantilevered beams being configured to move along the input direction; and a central pendulum mount between the cantilevered beams, the cantilevered beams extending on either side of the pendulum mount, substantially identical cantilevered beams (120, 122) that extend along the x-dimension, the cantilevered beams being configured to move along the input direction; and a central pendulum mount between the cantilevered beams, the cantilevered beams extending on either side of the pendulum mount, wherein the mechanism layer is shaped in the x and y dimensions with a fixed z dimension; first and second anchors that secure the first and second outside electrode structures, respectively, to the mounting surface of the base, wherein the first and second anchors each extend over a significant portion of an attachment area of the respective outside electrode structures; and an anchor that secures the pendulum mount to the base.