The letters “U.S.” (United States) have been personified by the fictional character of “Uncle Sam.” The letters “C.S.” (Confederate States) were personified by the fictional character of “Cousin Sallie/Sally.” The letters “C.S.A.” (Confederate States of America) were personified by “Cousin Sallie/Sally Ann.”
   
“Since we have thrown off our connection with Uncle Sam, and have become the Confederate States, we may call ourselves the children of Cousin Sally” was printed in the Charleston (SC) Daily Courier on February 13, 1861. “Cousin Sal” was used in this newspaper on May 1, 1861.
 
“Cousin Sally Ann” was printed in the Charleston (SC) Daily Courier on July 4, 1863. “Cousin Sallie” was printed in the Wilmington (NC) Journal on September 3, 1863. “Cousin Sallie Ann” was printed in the Charleston (SC) Daily Courier on May 4, 1864.
 
   
(Oxford English Dictionary)
Cousin Sally, n.
Forms:
α. 1800s Cousin Sallie, 1800s– Cousin Sally.
β. 1800s– Cousin Sally Ann.
U.S. colloquial (now historical and rare).
A nickname for: the Confederate States of America (see Confederate States (of America) at confederate adj. 3a).
1861   ‘Sigma’ Let. 10 Feb. in Charleston (S. Carolina) Daily Courier 13 Feb. 4/5   Since we have thrown off our connection with Uncle Sam, and have become the Confederate States, we may call ourselves the children of Cousin Sally.
1863   Ye Sneak yclepid Copperhead 17   On old Uncle Sam they pounced, And praised their Cousin Sally..; What harm had done poor Cousin Sal?
           
Newspapers.com
13 February 1861, Charleston (SC) Daily Courier, pg. 4, col. 5:
Correspondence of the Courier.
MONTGOMERY, ALA., February 10, 1861.
(...)
By the way, since we have thrown off our connection with Uncle Sam, and have become the Confederate States, we may call ourselves the children of Cousin Sally. I propose as a philosophical query whether, in view of the family alliance indicated in the word “Cousin,” we are to regard Uncle Sam as a foreign relation?
SIGMA.
 
11 May 1861, Miners’ Journal and Pottsville General Advertiser (Pottsville, PA), pg. 2, col. 3:
Disarrange the stomach of man, and he is powerless; disarrange the stomach of Uncle Sam, and Cousin Sal will come off best.
(From the Charleston Courier, May 1.—ed.)
 
28 May 1861, Daily Louisville Democrat (Louisville, KY), pg. 1, col. 3:
The initials “C. S.,” of the Confederacy, are made to stand for “Cousin Sally,” by the Southern secession papers. Hadn’t the Fire-eaters better call is Cousin Sal Amanda (salamander)?
 
11 June 1861, Evening Star (Washington, DC), pg. 2, col. 2:
THE NEW BORN SOUTHERN CONFEDERACY A GAL! The Mobile Tribune says:
“We must have a pet name for the Confederate States. Uncle Sam is turned over to the Yankees as an inveterate old curmudgeon. Let us make Cousin Sally our watchword and rallying cry. The thought would be in harmony with the chivalrous gallantry that should mark the character of the sons of the South. Who would not fight for Cousin Sally?”
 
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14 June 1861, Bangor (ME) Daily Whig and Courier , pg. 2, col. 4:
The Mobile Tribune says:
“We must have a pet name for the Confederate States. Uncle Sam is turned over to the Yankees as an inveterate old curmudgeon. Let us make Cousin Sally our watchword and rallying cry. The thought would be in harmony with the chivalrous gallantry that should mark the character of the sons of the South. Who would not fight for Cousin Sally?”
 
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17 June 1861, Louisville (KY) Daily Journal, pg. 2, col. 2:
The Mobile Tribune proposes “Cousin Sally” as a pet name for the Confederate States. The name is rather effeminate, but then her male fire-eating cousins could very appropriately be called Sally-manders.
 
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4 July 1863, Charleston (SC) Daily Courier “A Letter from New York,” pg. 2, col. 1:
We can talk secesh and drink to “Cousin Sally Ann” without being interfered with, ...
   
13 July 1863, Macon (GA) Daily Telegraph pg. 4, col. 4:
“Cousin Sally Ann” is the social soubriquet and familiar rendering of the initials “C. S. A.” among our copperhead friends at the North who prefer her to “Uncle Sam.”
   
Newspapers.com
17 July 1863, Camden (SC) Confederate, pg. 3, col. 2:
“Cousin Sally Ann” is the social soubriquet and familiar rendering of the initials “C. S. A.” among our copperhead friends at the North who prefer her to “Uncle Sam.”
 
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3 September 1863, Wilmington (NC) Journal, pg. 4, col. 2:
As it is, “Cousin Sallie” is nothing like it.
(...)
Yours respectfully, &c.,
ONE OF COUSIN SAL’S SONS
     
4 May 1864, Charleston (SC) Daily Courier, pg. 1, col. 3:
“Cousin Sallie Ann,” we learn, is fortunate in securing the services of patriotic friends who are willing to work for nothing for her on condition of her finding others to fight for them.”
 
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18 May 1864, Yorkville (SC) Enquirer, pg. 2, col. 3:
“Cousin Sallie Ann,” we learn, is fortunate in securing the services of patriotic friends who are willing to work for nothing for her on condition of her finding others to fight for them.
 
Newspapers.com
9 September 1864, Daily Davenport Democrat (Davenport, IA), “General News,” pg. 3, col. 2:
According to Confederate Interpretation “C. S.” means “Cousin Sal,” as “U. S.” stands for “Uncle Sam.”
   
OCLC WorldCat record
[Small broadsides from Confederate States of America]
Publisher: [Place of publication not identified] : [publisher not identified], [1861-1865?]
Edition/Format:   Image : Graphic : Picture : English
Notes:
Collective title devised by cataloger.
Broadside printed in red ink.
[1] Our Cousin Sally Ann is Oll Korrect—[2] Southern Rights! “Don’t Tread on Us.”—[3] [Confederate Flag]—[4] Jeff. Davis contemplating his latter end—[5] United we stand! Spirit of ‘76—[6] Marylanders Know their Rights, and will Maintain them!
Cousin Sally Ann stands for CSA or Confederate States of America ; Oll Korrect means all right, okay.