1870 census for Berlin, Green Lake, Wisconsin, family #76:
O'Brien, James, 47, b. Ireland, brick mason
O'Brien, Bridget, 48, b. Ireland
O'Brien, Mary, 21, b. Conn.
O'Brien, Julia, 20, b. Conn.
O'Brien, John, 18, b. Conn.
O'Brien, Patrick, 17, b. Conn.
O'Brien, Cornelius, 15, b. Conn.
O'Brien, James, 13, b. Wisc.
O'Brien, Bridget, 10, b. Wisc.
O'Brien, Ellen, 8, b. Wisc.
O'Brien, Katie, 5, b. Wisc.

1900 census for Brainerd, family #69:
O'Brine, Con, head, b. Nov 1854 Conn.
O'Brine, Lizzie, wife, b. Feb 1867 Ireland, m 4y, 2 ch. 2 liv.
O'Brine, James W., son, b. Oct 1880 Minn.
O'Brine, Bertram, H., son, b. Mch 1882 Minn.
O'Brine, Mable A., dau., b. Oct 1883 Minn.
O'Brine, Gails P., son, b. Jul 1885 Minn.
O'Brine, Matilda M., dau., b. Sep 1887 Minn.
O'Brine, Julia, dau., b. Jan 1890 Minn.
O'Brine, Cornelius, son, b. Sep 1891 Minn.
O'Brine, Earl J., son, b. Mch 1897 Minn.
O'Brine, George F., son, b. Sep 1899 Minn.
(James - Cornelius are the children of Con's previous wife, Matilda, who died in 1893.)

1910 census for Brainerd, family #189:
... listing children born after 1900 ...
O'Brien, Mildred M., dau., 8, b. Minn.
O'Brien, Harriet E., dau., 6, b. Minn.
O'Brien, Edward T., son, 4, b. Minn.
O'Brien, Allace M., dau., 1 9/12, b. Minn.

      City Pays Tribute Thursday Rites
      For Con O'Brien, Leading Citizen

      All Brainerd today was shrouded in grief mourning in common regret the death of one of its outstanding citizens, a founder and builder of the city and, a man whose constant thought was the betterment and development of the place to which he dedicated his life's energy.
      Such grief extended to all parts of the Northwest to people who associated his name and that of the city of Brainerd synonymously.
      Such was the character of Cornelius O'Brien, familiarly known as Con O'Brien, whose friends were countless extending from the prominent to the obscure.

             Was Great Friend of Poor

      Among the varied expression of sympathy at his death was this one, unheralded and only known to Mr. O'Brien and unfortunates he has befriended, whom he cared for and imparted of his wonderful spirit to give them courage and help.
      Many of Mr. O'Brien's good deeds to charity and the relief of others are well known to this city. But—countless of his good deeds have never been recorded nor will they ever be. Unbeknown even to members of his immediate family he provided aid in clothing and food to poor people of this city. It was a generosity such as few have known.
      Immediate relatives completed today the arrangements for his burial-rites during which Brainerd will pause and consider his life anew and pay final tributes to his constancy of purpose in life, "peace and happiness to mankind."
      The St. Francis Catholic church of which he was a faithful member, supporter and worker will be the scene of his final tribute.
      The service will be conducted at 9 a.m., Thursday with Rev. Father James Hogan officiating. Burial rites will be conducted at Evergreen cemetery.

          Nearly 50 Years in Business

      Merchants will close their stores to pay in this tribute a small part of the great respect they hold for the man.
      Mr. O'Brien knew and loved work throughout his years of adult life. The desire to mingle in the business enterprises no doubt shortened his life, but as his friends knew him, his happiness in that of his family work and desire to assist others fully recompensed him and provided him happiness.
      Among his great hopes and ambitions in life was only one he virtually failed to accomplish—that of completing 50 years of business life in Brainerd. Such an ambition would have been realized had he lived until May, 1933.

               Active In Civic Affairs

      He was active in numerous civic and organization groups in the city and even during the past year when he was warned to avoid undue exercise and to slacken his duties in his store, the O'Brien Mercantile Co., Mr. O'Brien could not refrain from attending to difficult business matters and in these matters his keen intelligent mind was always sought by his associates.
      His death came Monday at 4:40 p.m. at his home, 307 1/2 South 8th street. Heart failure was the immediate cause of his death. He was reclining on a couch reminiscing with E. P. McCarthy, Minneapolis, an old friend. Passing his hand to his face and smiling faintly, he laid back on the couch. Knowing that his condition was critical Mr. McCarthy notified Mrs. O'Brien who in turn called members of the family residing in the city. These arrived at his bedside and were with him to his death. Rev. Hogan arrived before Mr. O'Brien died. Mr. and Mrs. Mike Reilly, old friends, had motored to Brainerd from Detroit Lakes earlier in the afternoon and visited with Mr. O'Brien.
      Many people wished Mr. O'Brien Easter greetings when he attended the Easter services at the St. Francis church Easter Sunday morning.

             Public Life Well Known

      The chronology of the life of Mr. O'Brien never can be fully recorded. Many of his fine deeds, acts and experiences in life will never be heard in full. However his public life as a citizen of Brainerd is well known.
      His obituary record reveals that he was born in Bridgeport, Conn., November 24, 1854, and that he spent his early youth in Berlin, Wis. When about 20 years of age he moved to Stillwater Minn., where he was married in 1880 to Miss Matilda McElroy. To this union were born seven children, James W., Bertram H., Mabel, Giles P., Maude, Juel and Cornelius, Jr.
      Mrs. O'Brien died in Brainerd on January 28, 1893, and three years later Mr. O'Brien was married to Miss Elizabeth Minogue. To this marriage six children were born, Earl J., George F., Mildred M., Harriet, Edward Thomas, and Alice M.
      Mr. O'Brien moved to Brainerd in 1882 and established himself in a retail business which first dealt extensively in logging. He founded the O'Brien Mercantile company, Brainerd's largest department store, in about 1900; O'Brien and Sons, wholesale grocers, in 1922, and had extensive real estate holdings in the city and county.
      Brainerd is indebted to Mr. O'Brien among many other interests for the attractive gateway to Gregory Park. The gateway is virtually a memorial to his life and his unstinting labors to promote Brainerd's welfare and future.
      Mr. O'Brien was twice elected mayor to the city of Brainerd, was honored by the members of the American Legion by being elected unanimously, one of the first "Dads" of that organization, was a member of the State Board of Appraisals during the governorship of John A. Johnson, and was a delegate to the democratic national convention in Baltimore in 1912.
      The Brainerd Chamber of Commerce respected highly his advice in matters in their jurisdiction. He was a charter member of the Chamber and a past president of it and one of its most loyal members. He was also a charter member of the A. O. H. [Ancient Order of Hibernians]
      The Brainerd Credit Bureau of which he was a member and a past president today announced the following resolution signed by its officials:
      "Because of the death of Cornelius O'Brien, a prominent citizen and active worker in all civic matters. We, the directors of the Brainerd Credit Bureau deem it advisable and proper that all stores within the city of Brainerd should close in his honor.
      "Therefore be it resolved by this board that all business places be requested to close during the funeral of our friend Con O'Brien.
      "In compliance with this resolution all business places in the city of Brainerd are requested to close between the hours of 8:30 a.m. and 11 a.m. on Tuesday, March 31, out of respect for the memory of Con O'Brien."
      Although Mr. O'Brien had been failing for the past two years, his death came as a distinct shock to all. He is survived by his wife, Elizabeth, his sons James W., Giles P., Cornelius, Jr., Earl J., George F., and Edward Thomas, all of Brainerd, and his daughters, Mabel O'Brien Smith and Mildred of Brainerd. Mrs. R. L. Siehl of Minneapolis, Sister M. Kathleen of Duluth, and Mrs. Theodore Ryan of Hutchinson, Kansas. (Brainerd Daily Dispatch, 29 March 1932, p. 1, c. 3 & p. 2, c. 5)

1930 census for Duluth, E.D. 54
(St. Mary's Hospital & Training School)
...
O'Brien, Harriet, Lodger, 26, b. Minn., f/m b. Conn./Irish Free State

1940 census for Hutchinson, Reno, Kansas, household #112:
Ryan, Theodore, head, 31, b. Kansas
Ryan, Alice, wife, 31, b. Minn.
+ 4 children - Terence, Quay, Connell & Dennis