It originates at Josephine Lake near the crest of the Cascade Range and flows generally east to join the Wenatchee River near Leavenworth.

Icicle Creek's drainage basin is mountainous and mostly undeveloped land within the Wenatchee National Forest and the Alpine Lakes Wilderness.

The final 6 miles (10 km) of the creek are moderately developed with scattered homes and pasture, a golf course, children's camp, a small housing development called Icicle Island Club, and the Leavenworth National Fish Hatchery.

[6] Icicle Creek's name comes from the Indian word na-sik-elt, meaning narrow canyon.

[2] Icicle Creek flows south from the lake through a deep and narrow valley.

After a few miles it turns southeast and its valley takes on a classic glacier-carved U-shape.

Spanish Camp Creek and its headwater tributaries drain the high alpine western side of Icicle Ridge from Grindstone Mountain to Cape Horn and Ladies Pass.

Boggy Creek joins from the north near the Rock Island Campground.

Eponymous campgrounds are located at the Ida and Johnny Creek confluences.

[2] According to monitoring data collected in 1993, Washington State Department of Ecology determined that the water quality of Icicle Creek was good and "met or exceeded expectations and is of lowest concern.