We report the Chandra detection of resolved X-ray emission of luminosity 3.5 × 1040 ergs s−1 (0.4–4.5 keV) and power-law energy spectral index = 1.5 ± 0.7 from a roughly 10 arcsec length of the north-west radio jet in NGC315. The X-ray emission is brightest at the base of the radio-bright region about 3 arcsec from the nucleus, and is consistent with a synchrotron origin. At a projected distance of 10 arcsec from the core, the jet is in approximate pressure balance with an external medium which is also detected through its X-ray emission and which has kT 0.6 ± 0.1 keV, consistent with earlier ROSAT results. The high spatial resolution and sensitivity of Chandra separates nuclear unresolved emission from the extended thermal emission of the galaxy atmosphere with higher precision than possible with previous telescopes. We measure an X-ray luminosity of 5.3 × 1041 ergs s−1 (0.4–4.5 keV) and a power-law energy index of = 0.4 ± 0.4 for the nuclear component.