Anna Benjamina Hemingway was a baby when her father died. In his Estate papers, in the petition by her mother for guardianship of all the children, she is called Anna Benjamina.  In 1861, she is living with her mother and step-father and her name looks more like Benjanna.  She is not found in the 1871 census with the family but she is again there in 1881. 
When Pauline dies in 1904, her half-sister is listed as living in Detroit. 
Mrs F. J. York, all the balance of my estate - half sister 199 Twentieth Street Detroit
So with that information I know where Anna or Benjanna or whatever she is going by is living in Detroit, presumably Michigan.
While searching for her mother after the death of Elijah, I found Harriet in a Detroit City Directory in the list of Bostwicks, I found her without her first name listed.
To find her I browsed through the directory to see the first name of York (wid Fredrick). She is listed as Anna B. 
On the 1920 census Anna, aged 65, is living at 15 Park Avenue with Ella, aged 44, (listed as sister) and Albert, aged 61 (listed as brother). Ella worked as saleslady in Department Store. Albert worked as signal man for the railroad. 
Anna died 5 May 1922 in Detroit, Michigan. Her date of birth is given as 2 December 1858. We know that this is incorrect because she was alive when her dad died. Her parents are listed as Benjamin Hemmenway and Harriet Webb. The informant is her half-sister Ella. She is buried in Evergreen Cemetery. 
 Benjamin Hemingway Estate File, H-9 RG 22, Series 6-2, (21 September 1851), York County Surrogate Court, microfilm MS 638 York County, Reel 84, Archives of Ontario, Toronto [incorrect date]
 1861 Census of Canada West, Ontario County, Pickering Township, p. 78. line 31, Elijah Bostwick household; digital image, Ancestry.ca (http://www.ancestry.ca : accessed 13 April 2015), citing microfilm C-1057, Library & Archives Canada, Ottawa.
 1871 Census of Canada, Ontario, Ontario County (district 47) Pickering Township (sub-district a), p 21, family 76; digital image Ancestry.ca (http://www.ancestry.ca : accessed 10 April 2015), citing microfilm C-9973, Library & Archives Canada, Ottawa.
 Pauline Hemmingway Estate Papers, Surrogate Court County of York (1904), microfilm MS 584 Reel 1100, Ontario Archives, Toronto.
 Detroit City Directory, 1903, entry for Bostwick; digital image, Ancestry.ca (http://www.ancestry.ca : accessed 20 April 2015) 1920 Census of United States, Michigan, Wayne County, Detroit Ward 14, Wayne, Michigan; Roll: 813; Page: 5B; Enumeration District: 416; Image: 216; digital image, Ancestry.ca (http://www.ancestry.ca : accessed 24 April 2015), citing microfilm T625
 Anna York Michigan death registration; digital image, Seeking Michigan (http://seekingmichigan.org : accessed 20 April 2015).
© 2015 Janet Iles