The birth dates for John and 3 children Tabitha, Chesley and John Wesley McCORMICK were taken from a BIBLE of a descendant Maurine WARNICK

Below are  four children, at least three are known to belong to John and Eliza, as I am not sure about David Alfred McCormick. Also, it is possible there were more children.

John McCOMMACK .
b.   20 Dec 1802  OH or Scotland
d.   21 Dec 1844 Wayne Co, IL
m.  abt 1820, in OH or IL
s.   Eliza
b.   20 Dec 1811
d.   after 1844 Wayne Co, IL
 

Four possible children of John and Eliza McCormick are:

1)	Tabitha Jane McCORMICK  b.   15 Nov 1829  (OH / IL) Note:  birth date from a Bible  d.   after 1860 Wayne? Co, IL  m#1   abt 1847 first  s#1    Charley UMPHREES m#2   abt 1849  s#2    Stuart M. HARGRAVE
2)	Chesley Charles "Liefer" McCORMICK b.  31 July 1822  (OH / IL) Note:  birth from a Bible  d.  1890   Wayne Co, IL  b.   Warren/New Church Cem  m#1  abt 1849  Wayne Co, IL  s#1   Susannah Jane MELTON m#2  Sept 1866  Christian Co, IL  s#2   Louisa J. AUSTIN;
3)	John Wesley McCORMICK b.  23 March 1836 Wayne? Co, IL  d.  Wayne  Co, IL
4)	David Alfred McCORMICK b.   18 Aug 1844 Wayne  Co, IL  d.   25 March 1905 Keene, Wayne Co, IL  b.   Warren/New Church Cem.  m.  17 June 1867  Xenia, Clay Co, IL  s.   Mary Ann "Millie" FORTH