Per the census records listed below, William was born 1850 not 1839. He is listed in the 1870 census record with Joseph and Talitha Cook Byrd who are his parents not Jesse and Nancy Byrd as some have suggested. My theory is one of the two sons of Jesse and Nancy's could have been named William. They both died young before 1850.

He married Mary Edna Hutson Nov 10, 1870 in Scott County, TN and Hassie Moore on Jun 25, 1896. She was born in 1855 per her death certificate and her obituary. She was 107 years old not 112 years old.

1870 United States Federal Census

Name: William Byrd

Age: 20

Birth Date: 1850

Birthplace: Tennessee

Dwelling Number: 33

Home in 1870: District 4, Scott, Tennessee

Race: White

Gender: Male

Post Office: Huntsville

Occupation: Farm Laborer

Inferred Father: Joseph Byrd

Inferred Mother: Telitha Byrd

Household Members Age

Joseph Byrd 44

Telitha Byrd 42

William Byrd 20

Nancy J Byrd 17

Elizabeth A Byrd 17

Peter 14

Sheanna (Sherman) 3

John L Cook (Brother-in-Law) 37

1880 United States Federal Census

Name: William Byrd

Age: 30

Birth Date: Abt. 1850

Birthplace: Tennessee

Home in 1880: Straight Fork, Scott, Tennessee, USA

Dwelling Number: 1

Race: White

Gender: Male

Relation to Head of House: Self (Head)

Marital Status: Married

Spouse's Name: Mary E. Byrd

Father's Birthplace: Tennessee

Mother's Birthplace: Tennessee

Occupation: Farmer

Household members Age

William Byrd 30

Mary E. Byrd 28

Lydia V. Byrd 8

Talitha Byrd 6

Cordelia Byrd 4

Emily C. Byrd 2

1900 United States Federal Census

Name: William B Byrd

Age: 50

Birth Date: Mar 1850

Birthplace: Tennessee, USA

Home in 1900: Civil District 4, Scott, Tennessee

Sheet Number: 1

Number of Dwelling in Order of Visitation: 6

Family Number: 6

Race: White

Gender: Male

Relation to Head of House: Head

Marital Status: Married

Spouse's Name: Hassa Byrd

Marriage Year: 1870

Years Married: 30

Father's Birthplace: Tennessee, USA

Mother's Birthplace: Tennessee, USA

Occupation: Farmer

Months Not Employed: 0

Can Read: Yes

Can Write: Yes

Can Speak English: Yes

House Owned or Rented: Own Home

Free or Mortgaged: F

Farm or House: F

Household members

Name Age

William Byrd 50

Hassa Byrd 39

Cordelia Byrd 24

Alexander Byrd 18

Isabelle Byrd 13

Maudie Murphee 10

John G Byrd 9

Winnie Murphee 8

Rhoda Byrd 6

Ollie Byrd 2

Edna Byrd 8/12

1910 United States Federal Census

Name: William Byrd

Age in 1910: 60

Birth Date: 1850

Birthplace: Tennessee

Home in 1910: Civil District 4, Scott, Tennessee, USA

Race: White

Gender: Male

Relation to Head of House: Head

Marital Status: Married

Spouse's Name: Hassie Byrd

Father's Birthplace: Tennessee

Mother's Birthplace: Tennessee

Native Tongue: English

Occupation: Farmer

Industry: General Farm

Employer, Employee or Other: Employer

Home Owned or Rented: Own

Home Free or Mortgaged: Free

Farm or House: Farm

Able to read: Yes

Able to Write: Yes

Years Married: 13

Household members Age

William Byrd Sr 60

Hassie Byrd 47

Cardelie Byrd 33

Isabell Byrd 23

Olie Byrd 12

Ednie M Byrd 10

Senie Byrd 8

1920 United States Federal Census

Name: William Byrd

Age: 69

Birth Year: 1851

Birthplace: Tennessee

Home in 1920

Civil District 1, Scott, Tennessee

House Number: Farm

Residence Date: 1920

Race: White

Gender: Male

Relation to Head of House: Head

Marital Status: Married

Spouse's Name: Hassie Byrd

Father's Birthplace: Tennessee

Mother's Birthplace: Tennessee

Able to Speak English: Yes

Occupation: Farmer

Industry: General Farm

Employment Field: Own Account

Home Owned or Rented: Owned

Home Free or Mortgaged: Free

Able to read: Yes

Able to Write: Yes

Household members Age

William Byrd 69

Hassie Byrd 64

Cordelia Byrd 43

Isabelle Byrd 32

Sena Byrd 18

Beatrice P Byrd (granddaughter) 5