The Grassy Island Range Lights are rare examples of a common nineteenth century navigational aid designed to help mariners entering and leaving a harbor. Range lights always came in pairs, the front (lower) light being shorter than the taller rear (upper) light. When a ship had these lights lined up, one above the other, the captain knew that it was on a safe course.

Originally, these two lights were situated on Grassy Island, which is located just outside the mouth of the Fox River in Green Bay. Because this low, narrow island prevented ships from making a straight approach into the port of Green Bay, workers cut a straight channel through the island. In order to guide ships through this channel the range lights were built along its east edge in 1872. These lights were originally part of a larger station complex that included a light keeper house, a boathouse, an oil house for the oil burned in the light, gardens, piers, and long walkways along the channel edges. All of these structures, except for the lights, were demolished when the channel was widened in 1966. Fortunately, the lights were saved and moved to shore in 1966, and were moved to their present location on the Fox River in 1999. They have since been restored.

Please note that the range lights are on private property and belong to the Green Bay Yacht Club, which is a gated property that is open only to its members. You can get a good general view of the range lights from the grounds of the U.S. Coast Guard Station, which is located next door, or from the river.