These are the only J. W. Hemphills I could find:

J. W. Hemphill, Private, Capt. G. W. C. Drane’s Company Infantry (Choctaw Silver Greys), recorded on a muster roll for this Choctaw County, Miss. company, organized for local defense, no other records

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J. W. Hemphill, Captain, J. W. Hemphill’s Company, 15th Regiment Mississippi Volunteers,* joined for duty and enrolled May 29, 1861 at Cornith by J. W. Hemphill for 12 months, advanced to Lt. Colonel June 6, 1861, resignation accepted August 9, 1861, no further records

* This company subsequently became Company I, 15th Regiment Mississippi Infantry

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John W. Hemphill, Private, Capt. Benjamin G. Humphrey’s Company, Mississippi Volunteers, joined for duty and enrolled July 2, 1861 in Sunflower County, Mississippi by Capt. Humphreys for the war, recorded on the March & April, 1862 muster roll as absent, wounded at Lee’s Mill, sick with wound in Williamsburg, died of wounds May 30, 1862 at General Hospital No. 1, Danville, Va., gunshot wound, effects left, 1 Knapsack, Clothing, 2 Blankets, description on enlistment, single, 19 year old Farmer, born in Missisippi, resident of McNult/McNutt?

* This company subsequently became Company I (Sunflower Guards), 21st Mississippi Infantry

M269: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Mississippi