First name may have been Johanna. Assuming marriage record to Frederick Knicht is correct, even though the last name is Gnich.
Sources
"Michigan Marriages, 1868-1925," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:N3KK-D21 : 18 February 2021), Frederick Knicht and Johanna Sielaff, 23 Apr 1870; citing Marriage, Detroit, Wayne, Michigan, , Citing Secretary of State, Department of Vital Records, Lansing; FHL microfilm 4208211.
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MW3G-CL4 : 26 August 2017), Anna Gnich in household of Frederick Gnich, Wyandotte, Wayne, Michigan, United States; citing enumeration district ED 268, sheet 518C, NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm 1,254,610.
"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M91Z-38J : accessed 23 October 2019), Anne Gnich in household of Frederick Gnich, Delray village, (east side), Wayne, Michigan, United States; citing enumeration district (ED) 201, sheet 1B, family 16, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,755.
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MZWK-B7X : accessed 23 October 2019), Anna Gnich in household of Allanzo Charette, Detroit Ward 20, Wayne, Michigan, United States; citing ED 618, sheet 15B, line 76, family 358, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 812; FHL microfilm 1,820,812.
"Michigan Death Certificates, 1921-1952," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:KFWT-928 : 13 March 2018), Anna C Gnich, 28 Jul 1922; citing Detroit, Wayne, Michigan, United States, Division for Vital Records and Health Statistics, Lansing; FHL microfilm 1,972,962.
Find a Grave, database and images (www.findagrave.com/memorial/148871073/anna-gnich : accessed 19 June 2021), memorial page for Anna Seiloff Gnich (30 Nov 1847–28 Jul 1922), Find a Grave Memorial ID 148871073, citing Woodmere Cemetery, Detroit, Wayne County, Michigan, USA ; Maintained by J. Miller (contributor 48636935) .
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