Fifteenmile Creek is a tributary stream of East Deep Creek, in Juab County, Utah and Tooele County, Utah. Fifteenmile Creek has its source at an elevation of 10,280 feet / 3,133 meters, on the west slope of Red Mountain in the Deep Creek Range and in the at 39°47′54″N 113°57′06″W / 39.79833°N 113.95167°W. It flows north northwest to its confluence with an unnamed stream, at an elevation of 6,025 feet / 1,836 meters, 0.75 miles north of Goshute. There the confluence forms East Deep Creek, ten and a half miles south southeast of Ibapah.