"New York, U.S., State Census, 1865" Ancestry Sharing Link - Ancestry Record 7218 #774990 (accessed 28 April 2022) Ann Casey (30) servant in household of Chas E Hill (38) in Brooklyn, Kings, New York, USA.
Possible death record:
"New York, New York City Municipal Deaths, 1795-1949," database, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:2W7Z-MN8 : 3 June 2020), Elisa Ann Casey, 28 May 1868; citing Death, Brooklyn, Kings, New York, United States, New York Municipal Archives, New York; FHL microfilm 1,323,670.
Or, possibly this record of an Anna Careg (sp ?) with the family in 1880, birth year is different... Robinson-27225 22:35, 28 April 2022 (UTC)
"United States Census, 1880," database with images, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:MZNX-8GD : 14 January 2022), Anna Careg in household of H. Ward Beecher, Peekskill, Westchester, New York, United States; citing enumeration district , sheet , NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm