You can search land records to try to determine when your ancestor arrived and left any given area. Many times a family would move on before being able to sell its property. In such instances the new residence's location will be mentioned in the old county's deed books when the land is sold. This will give you critical information with which to continue your search and also provide evidence that the John Case who sold 150 acres in Greenbrier County, Virginia in August of 1838 is probably the same John Case who purchases 200 acres in Darke County, Ohio in June of that year. This information can be extremely helpful if you have lost an ancestor between censuses.
Relationships are another benefit to be found in land records, sometimes.
There are also times when the descriptions of the land will include relationships. This was especially true when the description was done using chains and rods, which required including the names of the owners of adjacent properties. While relationships may not appear, the names themselves may prove familiar and useful to you. Land records generally have two types of indexes. The grantor index is an index to those who are selling the land and the grantee index is an index to those who are buying the land.