November 1, 1866, the first Cape Arago Lighthouse was illuminated. The octagonal, wrought iron tower was capped with a lantern room housing a fourth-order Fresnel lens and was supported by spindly metal legs. Located at the northern end of the island, the tower was linked via a wooden walkway to a one-and-a-half-story wooden keeper's dwelling, constructed near the southern end of the island.
