The ownership of a piece of land is a matter of public record. All you need to do is to go to the appropriate county office and look up the deeds that were recorded against a property. That chain of deeds will show you who owned the land at what time, who he bought it from and who he sold it to. As you go further back in the record, you may be able to see how the land was subdivided from a larger piece of land, as well.
Search For the County Website
Visit the website for the county in which the land is located and open the property information search or the Geographic Information System mapping tool -- whichever that particular county offers.
Type in the Property Address
Enter the property's address into the tool, or, if you're using a GIS system, zoom the map into the property and use the "property information" tool to display the property's ownership information.
Many counties won't give you all of the historical data on the property through their websites, but you should be able to find out the current owner and when she bought the property. You might also be able to get the name of the previous owner.
Stop by the Recorder's Office
Visit your county recorder's or clerk of deeds' office. There, you can use their computers to search for historical documents recorded against the property, using the address or even the legal description.
You may see a whole range of different documents recorded, but the most common ones that are used to transfer ownership are the grant deed, the warranty deed and the quitclaim deed. If you work backwards through these documents, you should be able to build a history of the property.
Sometimes, counties haven't digitized their entire store of documents. When you need to search past the beginning of their database, you may need to request archived records or use records that are preserved on microfiche.
Pay the Title Company
Hire a title company to conduct a title search and create a history for you, if you can't do it for yourself. Title companies sell insurance that protects people's ownership rights in property, so they're very good at tracking a property's ownership. Since it won't be doing the search for the purpose of you buying title insurance, it will probably charge you to research a title history, but you might find that it's worth the expense.
Use Genealogy Sites
Another source for land ownership data can be online genealogy research sites. However, you may have to pay to access the data that they have stored.