I've tried various spellings with no joy: Cassaday, Casaday, Cassady, Cassetty, & Cassidy
I take it you know of his family, providing the names of his parents, occupations, etc., may be helpful in tracking him down through the Federal census.
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James H. Cassidy
Residence Chatham County GA;
Enlisted as a Private (date unknown).
"G" Co. GA 1st Infantry (Killed at Battery Wagner)
(Last name; Cassidy or Cassiday.)
Sources used by Historical Data Systems, Inc.:
- Roster of Confederate Soldiers of Georgia 1861-1865
Company G: Tattnall Guards, Chatham County, (Archibald C. Davenport). This company was originally Captain A.C. Davenport's Independent Company, 3rd Brigade, Georgia State Troops. http://www.nwinfo.net/~jagriffin/1st.htm
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James H. Cassady, Private, Company G, 1st Georgia Infantry (Olmstead's), name appears on a receipt roll for clothing issued July 8, Sept. 9, Oct. 7, 1863, killed at Fort Johnson, James Island, South Carolina August 12, 1863, no other records
Company G, 1st Vol. Ga. Inf., formerly Davenport's unattached Co. "Tattnall Guards", Re-organized April 29, 11862 for War, previously in service of State of Ga.,
A. C. Davenport, Capt.; Jos. B. Ri;ley, 1st Lieut.; Jno, N, Lewis, 2nd/1st Lt.; Chas. S. Hardee, 2nd Lieut.; Benj. T. Cole, 2nd/1st Lt.; Cyrus B. Carter, 2nd Lieut.; Jno. D. Hopkins, 2nd Lieut.
Company G Muster-in roll dated April 24, 1862 at Oglethorpe Barracks, Savannah, formerly known as Capt. Davenport's Unattached Company, Tattnall Guards, Georgia Infantry
April 24 to June 30, 1862, stated at Oglethorpe, Barracks
Oct 1 to Nov. 31, 1862, stationed at Camp Hearns [?]
Note: These are the only two company muster rolls which have survived to be recorded in the Compiled Service Records. Thus, we have no way of ascertaining Cassaday's enlistment data
M266: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Georgia
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1st Regiment, Georgia Infantry (Olmstead's)
1st (Mercer's-Olmstead's) Volunteers Infantry Regiment was organized prior to the war with militia companies from Savannah. Other members were from Quitman, and the counties of De Kalb, Oglethorpe, Washington, and Tattnall. After entering Confederate service it wsa disciplined at both heavy artillery and infantry. The regiment served on the coast with a detachment at Savannah and another at Charleston until May, 1864. It then was assigned to General Mercer's Brigade and during the Atlanta Campaign, July 20 to September 1, reported 11 killed, 31 wounded, and 6 missing. Transferred to J.A. Smith's command it continued the fight with Hood in Tennessee and on December 21, 1864, had only 52 men present for duty. Later it saw action at Bentonville and surrendered on April 26, 1865. The field officers were Colonel Hugh W. Mercer and Charles H. Olmstead, and Lieutenant Colonels Martin J. Ford and William S. Rockwell.
http://www.itd.nps.gov/cwss/regiments.cfm
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Here are two possible men I found in the 1860 Georgia & Tennessee Census
1860 United States Federal Census about James C Cassidy
Name: James C Cassidy
Age in 1860: 19
Birth Year: abt 1841
Birthplace: Georgia
Home in 1860: Fairplay, Cherokee, Georgia
Gender: Male
Post Office: Fosters Mills
Household Members:
Name Age
Mitchel Cassidy 41 Brick Mason
Sarah C Cassidy 32
James C Cassidy 19
Mary Cassidy 17 Student
Sarah C Cassidy 14
James C Cassidy 12
Margarett Cassidy 6
John W Cassidy 3
Henry Cassidy 1
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1860 United States Federal Census about James Cassady
Name: James Cassady
Age in 1860: 22
Birth Year: abt 1838
Birthplace: Tennessee
Home in 1860: District 11, McMinn, Tennessee
Gender: Male
Post Office: Athens
Household Members:
Name Age
Nancy Cassady 47 Renter
James Cassady 22 Farm Laborer
Phebe E Cassady 16