Powder House Island (also known as Dynamite Island) is an artificial island on the lower Detroit River in southeast Michigan, directly adjacent to the Canada–United States border. It was constructed in the late 1880s by the Dunbar & Sullivan Company to store explosives during their dredging of the Livingstone Channel. It was constructed in a successful attempt to circumvent an 1880 court order forbidding the company to store explosives on nearby Fox Island.