It is not always possible to tell, but consider finding out where the boundaries of your ancestor's property came from. A survey plat of my ancestor's farm in 1940 indicated that the boundaries of his 100+ acre farm came from:
- the section line
- the railroad
- a hedge row
The railroad is no longer there, but that "line" still exists as the property north of the line is not owned by the person who owns my ancestor's farm today.
Learning a little about the "lines" of your ancestor's property may give you a quick history lesson. It may even give you a few genealogical clues in the process.
And if your ancestors were city dwellers, consider learning the origin of the name of the street on which they lived.