Musquacook Stream is a tributary to the Allagash River in the North Maine Woods. The stream originates in a chain of lakes in Maine range 11 townships 10, 11 and 12. The flow sequence is from Clear Lake through Fifth Musquacook Lake into Fourth Musquacook Lake in Piscataquis County; and from Fourth Musquacook Lake through Third Musquacook Lake, Second Musquacook Lake, and First Musquacook Lake into the Allagash River Musquacook Deadwater in Aroostook County.