I did a search of Senasac (and the spelling variations) and in that time frame, there are Sanasac families in seemingly only two counties in Minnesota. (I used the free search site familysearch.org)
Blue Earth County, including a family living in Mankato, and Decoria township in Blue Earth County.
The other location of Sanasac in Minnesota is Alton township in Waseca county, MN, and then it seems that family moved to Wisconsin.
There is a Sarah Sanasac married in Minnesota to Clarence Cahill.
groom's name: Clarence S. Cahill
bride's name: Sarah J. Sanasac
date: 15 Oct 1906
marriage place: Janesville township, Waseca County, Minnesota
indexing project (batch) number
source film number 1320462
So it is possible that Sadie was born in Minnesota, even if her family was moving through, possibly staying with relatives along the way? One of those two families could be related. It's a very uncommon name.
Here is a website with the historical societies for those counties of Waseca and Blue Earth in Minnesota:http://www.mnhs.org/localhistory/mho/chsclo.html
A birth in Texas gives no added info on Sadie.http://files.usgwarchives.net/tx/nacogdoches/vitals/births/1...
Armstrong,J D 3-19-1928 M Sadie Senesac R. L. Armstrong
I do find it interesting that at findagrave.com I see her name is shown as Sadie J. Senasac
I am not getting findagrave.com to work this morning, but this was what I found when I googled Sadie Senesac
Robert Lee Armstrong (1884 - 1968) - Find A Grave Memorialwww.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=58526559C...
You +1'd this publicly. Undo
Sep 11, 2010 –
Husband of Sadie J. Senesac md 23 Oct 1904 Naco, Naco Co Tx. *Note: Death certificate informant Minnie Armstrong Census 1910 Douglass ...
If they were married Oct. 23, 1904 in Naco, Naco County Texas? She should be on the census of 1900 - if Texas has that as a census date.
Nacodoches must be Naco.
sorry I couldn't find anything more definitive. Sadie is a nickname for Sarah.