This should give you some other places to search.FamilySearch database of the 1880 Census, Assumption, Christian, IL:Henry LIVINGSTON, 64, KY KY PA; wf. Mahala, 64, KY IRE VA; nephew & nieces:Joseph ROBERTSON, 41, KY IRE VA; Ida M., 13, MO KY IN; Mary C., 10, MO KY IN.
With the above names combined, that must be your Mahala.There were several William ROBERTSON entries on the 1880 Census.I'm not sure that this is the right one, but ages sometimes were exaggerated once a person was around eighty.Pilot Grove, Moniteau, MO:Wm. ROBERTSON, 82, KY Scot VA; wf. Catharine, 70 NC Germ NC; servants Jas. DOIL, Nancy GREGORY, John LEIGE.
I wonder whether Polly had a sister Mary. Polly was usually a nickname for Mary. This might be a relative: Gallatin, Clay Co., MO, 1880:Isaac LANGSTON, 63, KY; wf. Emmerine, 55, KY.
I didn't see any Allan in 1880.Could he have been listed as one of these?
In Sugar Ck., Harrison, MO: Allen ROBERTSON, 36, KY KY KY, wf. Margaret, 27.
Kearney, Clay, MO:Alin ROBERSON, 32, MO KY KY, wf. Alice.
Marble Ck., Jessamine, KY:Allen ROBERSON, 60, KY, dau. Laura & her husband Heny WEST & ch. Catie, Maggie, & Harry W. WEST, all b. KY.
Do you have the dates and places for the rest of the line down to you so you could post info for those that are deceased?SSDI might help you to find death certificates and obituaries.You could also follow them on censuses up to 1930.
I checked the name Rainey ROBERTSON but only found Negroes, but that might indicate other relatives being in the U. S. earlier.
A Google search brings up your messages and also
Joseph Rainey ROBERTSON d. 1833, bu. near Frankfort, KY; came fr. Scotland to Indiana & then to Kentucky.Eight ch. (no further info on Sol. R., Eliz., Mahala, or Mary Ann.)
1. James (7 Je. 1798 - Jan. 1883, bu. nr. Frankfort, KY) m. 1817, Martha A. METCALF (1800 - 1872).They had John W. (1819 - 1885); Susan B. (1823 - 1851); Jas. J., b. 1826; Mary E. (1828 - 57); Zac. Finch (22 Oct. 1830 - 9 S 1881); Isabelle (1834 - 64); Benj. F., b. 1840; Henry Clay, b. 1842; & Martha E.
2. Wm., b. 1803, m. _ NEVINS, had 13 ch. incl. Sol. & Merit.
4. Johnson m. Mary LANGSTON & had Robert, Allen, Samuel, & L.D.
Mattoon, Coles, IL, 1880: Zach ROBERTSON, 50, plasterer, KY KY KY; wf. Rebecca J. [MORRISON], 50, PA PA PA; ch. Oscar C., 23, IN; Mattie J., 18, IL; Belle, 16, IL; other C. H. BOWEN, 21, NY.
not my family