Here's something.
1840 US census, in Cobleskill, Schoharie, NY -- looks like just under 40 miles east of Troy on what is now Interstate 88.
Oops, I left out the name! --
William Lockhard. They do not seem to be there in 1850.
Nine free white persons in total.
3 are aged 20-49.
5 are under 20.
So 1 is 50 or over.
Two parents, two adult children, and five younger children?
Children under 20 in 1840 could have been old enough to marry around 1850 (John, Jane and Margaret Lockhart in Troy/Lansingburgh).
And an Ellen born c1816 would have been 24ish in 1840 ... one of the adult children?
Margaret Henderson Lockhart Cloyde shows in 1850 as aged 60 / born in 1790, which would make her 50 in 1840. A little rounding in 1850, and she would be 49 in 1840.

Lockhart and Henderson married in 1811 so could have children nearly 30 yrs old in 1840.
So ... we need the breakdown! And is there a male person aged 5 to 9 in that household??
And here's one I somehow missed in the 1850 US census.
Fanny Lockhart, aged 38 / born c1812, no occupation stated, born Canada (or hm, immigrated from Canada?), in Albany. Oh my oh my -- she is a "Penientiary Convict"! For "Disorderly".
Not something one would likely be locked up for, for long. Our very bad luck that she decided to get disorderly the week of the census.
And oh my goodness, more -- this one spelled the German way.
William Lockhardt, aged 23 / born c1827, born in Canada, in Buffalo. Living in the household of Mary Jewett born in Scotland with a daughter born in Canada and a daughter born in NY, next door to a Thomas (Santas?), 27, born in Scotland.
And the occupation of this William Lockhardt and his next-door neighbour?
Upholsterer.
If he was in fact born in Canada, and if he is part of our Lockhart clan, this could help to date their presence in Canada before 1836.