I noticed Williss H Nichols owned some land in 1860 valued at $800, and John Robertson didn't own any.
On the preceding page there is a:

Name: George Robertson
Age in 1860: 62
Birth Year: abt 1798
Birthplace: South Carolina
Home in 1860: Not Stated, Oktibbeha, Mississippi
Gender: Male
Post Office: Starkville

Name: Nancy Robertson
Age in 1860: 62
Birth Year: abt 1798
Birthplace: Georgia
Home in 1860: Not Stated, Oktibbeha, Mississippi
Gender: Female
Post Office: Starkville

Name: Sarah Robertson
Age in 1860: 16
Birth Year: abt 1844
Birthplace: Mississippi
Home in 1860: Not Stated, Oktibbeha, Mississippi
Gender: Female
Post Office: Starkville

And in 1850

Name: George W Robertson
Age: 51
Estimated Birth Year: abt 1799
Birth Place: South Carolina
Gender: Male
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: Nancy Robertson
Age: 51
Estimated Birth Year: abt 1799
Birth Place: Georgia
Gender: Female
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: General Robertson
Age: 20
Estimated Birth Year: abt 1830
Birth Place: Georgia
Gender: Male
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: John Robertson
Age: 16
Estimated Birth Year: abt 1834
Birth Place: Georgia
Gender: Male
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: Elizabeth Robertson
Age: 14
Estimated Birth Year: abt 1836
Birth Place: Georgia
Gender: Female
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: William Robertson
Age: 12
Estimated Birth Year: abt 1838
Birth Place: Mississippi
Gender: Male
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: Calvin Robertson
Age: 10
Estimated Birth Year: abt 1840
Birth Place: Mississippi
Gender: Male
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Name: Sarah Robertson
Age: 6
Estimated Birth Year: abt 1844
Birth Place: Mississippi
Gender: Female
Home in 1850
(City,County,State): Not Stated, Oktibbeha, Mississippi

Looks like they migrated from GA abt 1837, maybe Harris County.