On 23 November 1854 in Vicksburg, Warren County, Mississippi, D. W. Keene was married to Sallie E. Wood. [Warren County, Mississipi, Marriage Register 1841–1866, page 291.]

1860 U.S. Census, Warren County, Mississippi:
Dwelling 841, Family 833
Wood, F., 62, carpenter, $3500 real estate, $5000 personal estate, born in Virginia
Wood, Matilda, 54, born in Virginia
Wood, John A., 17, born in Mississippi
Wood, Edward, 8, born in Mississippi
Under Fontaine’s listing the “in school” column is marked “2”, so apparently this signifies that both children were in school.
Dwelling 842, Family 834
Keene, D. W., 30, male, merchant, born in Massachusetts
Keene, Sarah, 28, female, born in Virginia
Keene, Clarence, 5, male, born in Mississippi
Keene, Lynwood, 3, male, born in Mississippi

The 1860 Vicksburg City Directory lists:
Keene D.W., firm Muller & Keene, res Grove st West side
[General Directory for the City of Vicksburg, H.C. Clarke, 1860]

1870 U.S. Census, Warren County, Mississippi:
Town of Vicksburg, new city limits
Page 338 (originally 48)
Dwelling 495, family 495
Klen, G. W., 37, male, white, Hard Ware Merchant, $1600 real estate, $3000 personal property, born in Massachusetts, eligible to vote
Klen, S. E., 39, female, white, Keeping House, born in Virginia
Klen, W.C., 14, male, white, born in Mississippi, in school
Klen, A.V., 9, female, white, born in Mississippi, in school
Klen, E. B., 2, female, white, born in Mississippi
Wood, F., 79, male, white, born in Virginia, eligible to vote
Wood, M., 66, female, white, born in Virginia
Wood, J. E., 28, male, white, Merchant, born in Mississippi, eligible to vote
Davis?, N., age illegible, female, white, Domestic Servant, born in Mississippi, in school
Reed, John, 14, male, black, Domestic Servant, born in Mississippi, in school

On 6 July 1876, Sarah E. Keene petitioned for administration on the estate of Dennis W. Keene, deceased, who died intestate. Administration was granted the same day. On 14 October 1880, she was summoned to show cause why annual accounts on the estate had not been filed, and was summoned again on 29 April 1889. Additionally, on 6 July 1876, Sarah E. Keene petitioned for guardianship of four minor children of Dennis W. Keene: W. Clarence Keene, age 20 on 16 December 1875; Annie V. Keene, age 14 on 21 January 1876; Robert L. Keene, age 8 on 14 February 1876; and Edna L. Keene, age 4 on 21 August 1875. [Warren County, Mississippi, Wills and Probate Records.]

The Proceedings of the Twenty-Fourth Grand Annual Convocation of the Grand Royal Arch Chapter of the State of Mississippi (1872) lists, under Returns of the Subordinate Chapters, Vicksburg, No. 3—Vicksburg, Warren County:
Members include D. W. Keene (page 52)
And for the Returns of Subordinate Chapters for the Year Ending December 27th, 1876, lists, under Vicksburg, No. 3—Vicksburg, Warren County:
DIED—D. W. Keene. (page 26)
[https://books.google.com/books?id=ZcAqAAAAMAAJ&...p;hl=en&sa=X&;ei=1it5Uq7_KoG9yAHl8oD4AQ&ved=0CEYQ6AEwAw#v=onepage&q&f=false]

A grave marker in Cedar Hill Cemetery, Vicksburg, Warren County, Mississippi, states:
Dennis W. Keene
Born May 16. 1833
Died June 9. 1876
A masonic symbol is on the top of the stone.
[Find a Grave Memorial #39549815.]