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This paper presents highly sensitive pressure sensors using piezoresistive nanowires. Our approach is based on nanowires locally fabricated on free standing structures with a high strain concentration. This strain concentration phenomenon amplifies the strain induced into nano-scaled sensing elements while the bulk materials are still at small strain regime, therefore enhancing the sensitivity of the sensors. For proof of concept, we utilized SiC nanowire fabricated using focused ion beam from an epitaxially grown thin film. Experimental results show significant 3-fold enhancement in the sensitivity in comparison to conventional structures, which is in good agreement with analytical modeling and numerical simulation. The proposed design shows potential for the development of miniaturized highly sensitive but robust nano mechanical-sensors.