Pendrith, an incoming senior at Kent State from Ontario, followed rounds of 68- 66 with the round of the tournament and is one shot up on first-round leader Justin Shin, also of Ontario by way of the University of New Mexico.
Tyler Dunlap held the overnight lead but shot even par 70 on a day that others went low. He's now alone in third place, two back of Pendrith.
A number of contenders are within striking distance, including Australia's Brady Watt (9-under, 4th), Beau Hossler and Cameron Wilson (6-under, T5) and Gavin Hall (5-under, T7).
West coast stars Bryson Dechambeau and Max Homa are at 4-under.
The final round in the prestigious 72-hole, no- cut event will be played Saturday from Niagara Falls Country Club.
Amateurgolf.com will have full coverage from the final round, including Walker Cup implications, live updates via Twitter and more.
