Between 1885 and 1925 the Presbyterian Church in Canada grew to become the largest church on the Prairies. Western Challenge documents that rise. Exploring the church's mission to the British settlers as well as its mission to the Native peoples and the non-Anglo-Saxon immigrants, this study examines how the church transformed itself and its ministry models to meet the challenges of the rapidly growing rural and urban populations of the Prairies. Special attention is paid to the church's experience in the Klondike and Near North prior to 1925. Western Challenge concludes by suggesting that the present-day Presbyterian Church is the true heir of this mission vision.