Between September and November 2018 Lawrence University conducted a geophysical survey, Phase I shovel testing, and a single Phase II 1.5 meter by 1.5 meter test excavation to determine if significant archaeological deposits are present on the north side of the historic Grignon Mansion. The survey and test excavations were undertaken on behalf of the City of Kaukauna in anticipation of constructing a replica of the summer kitchen that had once been located on the north side of the Mansion. The survey and excavations found what are thought to be remnants of the original summer kitchen, including a possible original subfloor and the foundation for a support post. Early glass found during the excavations suggest that the Grignon Mansion may have been built in the location of an earlier structure. The survey also identified what appears to be a large group of prehistoric longhouses to the northwest of the Mansion, here named North Kakalin Village. This area may contain archaeological deposits significant enough to be eligible for the National Register. Finally, it is recommended that a full Phase III excavation be undertaken in the area of the planned replica summer kitchen before construction proceeds.
Peregrine, Peter N., "Geophysical Survey and Phase I & II Testing at Wisconsin Site OU - 0115: The Grignon Mansion, Kaukauna" (2018). Archaeological Reports. 11.