Cocalico Creek is a 27.2-mile-long tributary of the Conestoga River in Lebanon and Lancaster counties. The source is near Stricklerstown in Millcreek Twp., Lebanon Co. The mouth is at the confluence with the Conestoga River at Talmage in West Earl Twp., Lancaster Co.
The name of the creek comes from the Lenape, meaning "snake dens". It comes from the Lenape word Gookcalicunk (pronounced "Gook Cal-eek Unk), which means "Snake Sleep Place" in English. The Lenape considered modern East Cocalico, West Cocalico, Clay, Warwick, Elizabeth, and Penn townships in Lancaster County, Mill Creek Township in Lebanon County, and the Middle Creek Wildlife Management Area as part of Gookcalicunk.
The Cocalico Creek watershed has a total area of 140 square miles and is part of the larger Chesapeake Bay drainage basin via the Susquehanna River.