The NRIS gives the location of the Holtz Site as "Address Restricted." However, Lovis (William Lovis (June 1971), "The Holtz Site (20AN26), Antrim Co., Michigan; A Preliminary Report", The Michigan Archaeologist, 17 (2)) gives the location of the site. Geo-coordinates are approximate.
Hoffman, Lisa M. (May 17, 2012). "Twin Falls Bridge Nominated". The Daily News. Iron Mountain, MI. Archived from the original on December 2, 2013. Retrieved July 20, 2013.
kbic-nsn.gov
The Sand Point site is an address restricted site, but is described in the following document as being "east and south" of the camping facility maintained by the Keweenaw Bay Indian Community, on land owned by the KBIC: Sand Point Concept Master Plan(PDF), Keweenaw Bay Indian Community, archived from the original(PDF) on April 26, 2012, retrieved November 30, 2011 The geographic coordinates given are approximate.
Staff. "Oscoda County Courthouse". State Historic Preservation Office. Michigan State Housing Development Authority. Archived from the original on May 13, 2013. Retrieved April 6, 2012.
The Sand Point site is an address restricted site, but is described in the following document as being "east and south" of the camping facility maintained by the Keweenaw Bay Indian Community, on land owned by the KBIC: Sand Point Concept Master Plan(PDF), Keweenaw Bay Indian Community, archived from the original(PDF) on April 26, 2012, retrieved November 30, 2011 The geographic coordinates given are approximate.
Hoffman, Lisa M. (May 17, 2012). "Twin Falls Bridge Nominated". The Daily News. Iron Mountain, MI. Archived from the original on December 2, 2013. Retrieved July 20, 2013.
Staff. "Oscoda County Courthouse". State Historic Preservation Office. Michigan State Housing Development Authority. Archived from the original on May 13, 2013. Retrieved April 6, 2012.