Long Tail Point Light guided vessels through the shifting shallows at the southern end of Green Bay, beside the channel into the city of Green Bay. First built in 1848 of fieldstone, it was illuminated by oil lamps and later fitted with a Fresnel lens, but unstable conditions soon surrounded it with water and forced its abandonment in 1859. Successive replacement lights were built farther north and later offshore as the shoreline and channel changed, with automation arriving in 1936. The offshore structure was destroyed in 1973 and replaced by a skeleton tower. The surviving ruin of the first stone tower remains the chief physical reminder of this repeatedly rebuilt navigation site.