Here's what I'm seeing and I believe Anna died after Patrick (d.1907?) in 1918.
1880 census for reference:
https://www.familysearch.org/ark:/61903/1:1:MWJJ-87LPatrick Merrigan 50
Ann Merrigan 45
William Merrigan 20
Mary Merrigan 18
Theressa Merrigan 15 <---------------
Edward Merrigan 13
Annie Merrigan 11 <------------------
Robert Merrigan 8
Kate Merrigan 4 <-------------------
John Merrigan 1/12
==================
Daughter Thressa died in 1924
Married Roderick J Ryan in 1904.
Marriage:
https://www.familysearch.org/ark:/61903/1:1:QKJ4-4HKQ1910 census:
https://www.familysearch.org/ark:/61903/1:1:MGCJ-F9JName: Thressa Ryan
[Thressa Merrigan]
Age: 55
Birth Date: abt 1869
Birth Place: Phila, Pennsylvania
Death Date: 15 Oct 1924
Death Place: Philadelphia, Pennsylvania, USA
Father: Patrick Merrigan
Mother: Ann Cunningham <--------------------
=====
Daughter Annie died in 1945.
Anna Agnes Haughey
[Anna Agnes Merrigan]
Age: 76
Birth Date: 3 Jun 1869
Birth Place: Philadelphia, Pennsylvania
Death Date: 14 Oct 1945
Father: Patrick Merrigan
Mother: Anna Cunningham <-------------------
Spouse: Thomas J
=====================================
Daughter Kate/Catherine married August Bose in 1899
Marriage:
https://www.familysearch.org/ark:/61903/1:1:QKJW-47WFIn the 1910/1920 census Catherine & August are living at 2500 Clearfield St.
1910 census:
https://www.familysearch.org/ark:/61903/1:1:MGCX-GSV1920 census:
https://www.familysearch.org/ark:/61903/1:1:MXMJ-795=====
I belive this to be Anna's death record in 1918, though the age is off I'm sure it's her. All other info matches known information.
Her address on the death certificate is 2500 Clearfield St. The informant is listed as Annie Bose of the same address. I think "Annie" may have been daughter Catherine's middle name or an error?
DC: Name: Mrs Anna Merrigan
[Mrs Anna Cunningham]
Age: 70
Birth Date: abt 1848
Birth Place: Ireland
Death Date: 10 Dec 1918
Death Place: Philadelphia, Philadelphia, Pennsylvania, USA
Father: Patrick Cunningham
Mother: Bridget Shea
---------
The Philadelphia Inquirer
Philadelphia, Pennsylvania
Thursday, December 12, 1918 - Page 18
MERRIGAN---Dec. 10. ANN, widow of Patrick Merrigan. Relatives and friends are invited to attend funeral. Fri.. at 7.30 A. M .. from the residence of her son-in-law, August Bose. 250O E. Clearfield st. Solemn requiem mass at Church of the Nativity, at. S A. M. Int. at Holy Cross Cem.