Mount Bullen is a steep, rugged peak on the western edge of Washington’s North Cascades in the Boulder River Wilderness, where sharp relief shaped by uplift, faulting, and repeated glaciation defines the landscape. Its slopes drain into the Boulder River headwaters, and its faces rise abruptly above Bullen Lake and the river below. The mountain was named for Chauncey Bullen, a government log scaler killed in 1919, though older maps misspelled it as Mount Bullon until the official spelling was adopted in 1990. Its first recorded ascent in 1936 reflected the mountain’s harsh, demanding character, which is reinforced by the area’s wet, avalanche-prone marine climate.