Individual Details

He was old enough to make a deed May, 1818, so he was at least 21 by that time.

Caswell Co NC Deeds
DB S, p.328 26 May 1818. Jacob Thomas of Halifax Co to Romulus M. Sanders of Caswell for $500, all claim to lot #24 in Milton being lot where Asa Thomas lived and died and inherited by Jacob Thomas an heir at law. Wit: H. Hooper, Thomas Bolton.

I believe this is his marriage - his wife was apparently Nancy in the 1850 census.
Jacob Thomas m. Nancy Lawson, 10 Mar 1819, Halifax Co VA
Virginia Marriages, 1740-1850; Ancestry.com
Irvin Brandon was Bondsman; Jacob's stepfather was a William Brandon.

These would seem to be Jacob's transactions in Caswell, even though he lived in Halifax Co.
Caswell DB T, p.85 18 Mar 1819 William Mutrey & Reuben Walton to Jacob Thomas for $140, part of lot #5 in E. Milton, east side Country Line Cr. adj David Mitchell, John Oliver's warehouse. Wit: J.P. Sledge, Jesse Walker
DB T, p.32 29 Apr 1819 William Mutrey to Jacob Thomas for $300, Lot #29 in E. Milton on High St., adj. James Rainey, James Mitchell, James Calloway. Wit: Hugh Campbell, David Taylor
DB Y, p.201 14 Nov 1829 Jacob Thomas of Halifax to Joseph McDowell & Stephen Dodson of Caswell for $30.50, Lot #29 in E. Milton at juncture of road from James Rainey to High St, adj James Mitchell, James Calloway. Wit: R. W. Thomas, Malbon Kenyon
DB Y, p.203 8 Dec 1829 Jacob Thomas of Halifax to Joseph McDowell of Caswell for $1.75, part of lot #5, east side Country Line Cr adj David Mitchell to John Oliver Warehouse. Wit: Jno B. Pugh, Malbon Kenyon

Probably found Jacob Thomas in Halifax Co, 1820:
Jacob Thomas: 1m age 16-26. 2f -10, 1f 26-45.

1830, Halifax Co VA
Jacob Thomas: 2m -5, 1m 15-20, 1m 30-40 [he would be about 34]. 3f age 5-10, 1f age 30-40.

Caswell Co WB M, January Court 1832
p.81 John O. Brackin, adm. estate of Durrett Richards. Collected debt from Jacob Thomas. Paid Milton Gazette for ad. Paid expenses for travel to Pittsylvania Court House, VA.

1840, Halifax Co VA
Jacob Thomas: 1m -5, 2m 10-15, 1m 50-60. 2f 5-10, 2f 15-20, 2f 40-50

Possible family of Jacob:
1850, Halifax Co VA.
Probable Widow, Nancy Thomas, age 55, b. VA
Jacob, age 21. Virginia, age 16.

Birth

Bef May 1797

Father	Jacob Thomas (1767 - 1803)
Mother	Hannah Farley ( - )
Sibling	James Madison Thomas (1794 - )