M, #6880, b. 14 March 1824, d. between 1886 and 1888
| Birth* | 14 March 1824 | Isaac Underwood (son of Samuel) was born on 14 March 1824 age 26 in 1850, age 36 in 1860, date from Kay.1 |
| (Witness) Census1830 | 1830 | He is assumed to be one of the household of Samuel Underwood in the 1830 census, pg 184, no twnshp listed, Tyler Co., West Virginia, who has Underwood, Samuel Jr 2m0-5 (Daniel & John) 3m5-10 (Jonathan, Isaac & Solomon) 1f0-5 (Amy) - very faint, doesn't look like either parent has a tickmark but they should be 1m30-40 (Samuel) and 1f30-40 (Margaret). |
| Marriage* | 7 December 1848 | Isaac Underwood (son of Samuel) married Eliza Doak on 7 December 1848. |
| Census1850* | 1850 | Isaac Underwood (son of Samuel) appeared on the 1850 census as the head of household, pg 331 #121-121, District 61, Tyler Co., West Virginia, along with Eliza Doak and Agnes Underwood . His info on the census included Underwood, Isaac 26 b.VA farmer $300. |
| Census1860 | 1860 | Isaac Underwood (son of Samuel) appeared on the 1860 census as the head of household, pg 145 #999-999, Moores Post Office, Tyler Co., West Virginia. His info on the census included Underwood, Isaac 36 b.VA farmer $1000-$506. |
| Census1870* | 1870 | He appeared on the 1870 census as the head of household, pg 318 #168-168, McElroy Twnshp, Tyler Co., West Virginia, along with Eliza Doak, Samuel Underwood, Robert Underwood, Martha Underwood and Silas Martin Underwood . His info on the census included Underwood, Isaac 46 VA $2500 land. |
| Census1880* | 1880 | Isaac Underwood (son of Samuel) appeared on the 1880 census as the head of household, ED 181 pg 40a #129-129, McElroy Twnshp, Tyler, West Virginia, along with Eliza Doak and Silas Martin Underwood. His info on the census included Underwood, Isaac 56 b.VA farmer. |
| Death* | between 1886 and 1888 | Isaac Underwood (son of Samuel) died between 1886 and 1888. |
| Will* | 3 May 1886 | He left a will on 3 May 1886 at Tyler Co., West Virginia; will bk 3 pg 291 names children. |
| Probate* | 25 January 1888 | His estate was probated on 25 January 1888 at Tyler Co., West Virginia. |