We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey .
PSR J1856+0245 has a spin period of 81 ms , a characteristic age of 21 kyr , and a spin-down luminosity \dot { E } = 4.6 \times 10 ^ { 36 } ergs s ^ { -1 } .
It is positionally coincident with the TeV \gamma -ray source HESS J1857+026 , which has no other known counterparts .
Young , energetic pulsars create wind nebulae , and more than a dozen pulsar wind nebulae have been associated with very-high-energy ( 100 GeV - 100 TeV ) \gamma -ray sources discovered with the HESS telescope .
The \gamma -ray emission seen from HESS J1857+026 is potentially produced by a pulsar wind nebula powered by PSR J1856+0245 ; faint X-ray emission detected by ASCA at the pulsar ’ s position supports this hypothesis .
The inferred \gamma -ray efficiency is \epsilon _ { \gamma } = L _ { \gamma } / \dot { E } = 3.1 % ( 1 - 10 TeV , for a distance of 9 kpc ) , comparable to that observed in similar associations .