Hi Sharon,
This family is listed in the 1860 census of Elba, Knox County: Thomas 44 IOM; Mariah 43 IOM; Elisabeth 3 Illinois; Mariah 1 Illinois; Ruth 1/2 Illinois
1870 census Elba: Thomas 54 IOM; Maria 44; Mary 4. 14 Illinois; Maria 12 Illinois; Ruth 10 Illinois; Thomas A. 8 Illinois
1880 Elba: Alfred 18 Illinois; Maria sister 21 Illinois; Ruth 20 sister Illinois.
Statewide Illinois marriage index gives Thomas H. Shanahan/Ruth M. Stalker 5/29/1890 Knox County
In 1870 Edward Stalker is living next door to Thomas:
Edward 45 IOM; Jane 45; Catherine 18 New York; Edward 16 New York; Ann J. 14 New York; Elizabeth 11 New York; Thomas H. 8 New York; Isaac J. 2 Illinois; Frances 5/12 (Dec) Illinois.
If you go to Ancestry.com, click on search records, plug in the name Thomas Stalker, go down to trees and community, Ancestry Family trees, on the 4th page you will find a family tree which shows Thomas Stalker as the son of Thomas and Catherine Lord. Also Thomas and Catherine's son Edward, whose first wife was Eleanor Christian, and second wife Jane Kneale.
Following the information in the family tree that Thomas Stalker died in Rochester New York, 1863, I searched the 1860 Rochester census, and found Thomas (no Catherine) with Edward and Jane living next door.
Catherine was said to have died in Rochester in 1853, so I searched the 1850 Rochester census. Not there.
So immigrated 1850-1853???
Keep paging through the Family Trees on Ancestry. There are a couple of people, at least, researching this family.
If you go to this website:
http://home.connexus.net.au/~mlord/famhist2.htm
you will find a history of the Lord family which includes a mention of Catherine who married Thomas Stalker.
I caution you to take all of this with a grain (or several) of salt, and recheck the information, using the original souces, (marriage records, baptisms, census, death records, wills, etc).
Good luck!