Tank led Utah University to third place in the team event which was their highest placing in the history of the championships.
Utah had three athletes in the top 10. Fellow Brit Bella Williams came seventh, with Sarah Feeny 10th.
Tank, who ran for Great Britain at last season’s European Cross Country Championship, was only 17 seconds behind the leader, Fiona O’Keffe, after clocking 19.49.6 for the 6k course.
Utah head coach Kyle Kepler said: “It was the best finish in our program history since entering the Pac-12 and I couldn’t say enough about Poppy and Bella.”
There were also top 25 finishes in cross country championships on Friday for City of Plymouth’s Victoria Weir and Erme Valley Harriers’ Will Battershill.
Great Britain international Weir, competing for Portland University, finished 21st at the West Coast Conference Championships at Woodley Lakes Golf Course. Weir was Portland’s third scorer as they finished runner-up in the team event.
Fellow international Battershill, running for Harvard University, came 18th in the Ivy League Heptagonal Championships at Van Cortlandt Park in New York. He was part of the Harvard team which took runners-up spot and equalled their best finish since 1984.