I have a listing currently that has a shared driveway between two properties that since the original sales have been owned separately. By the way neither current owner wants responsibility for maintenance. Boundary disputes are not uncommon.
County records wil clearly state the boundaries of each property and as Melissa pointed out a survey is the best way to get a clear understanding of exactly what those boundaries are. A deed specifying that the property line "...commencing at the northeast corner of said northeast quarter, thence south along the westerly line thereof, 1176.16 feet and thence south 89 degrees east, a distance of..." while completely accurate leaves most people scratching their heads.
Many county web sites include maps and diagrams of properties by owner, address or Parcel ID. In many cases (more metropolitan areas) these can even be displayed with satellite imagery as the background allowing for a clear visual of the driveway and where the property line falls in relation to that driveway. These sites are normally reasonably intuitive to use but if you have issues or are still confused, a personal visit to your county auditor's office (the name will change based on the task assignments in your particular jurisdiction), a request for assistance from your friendly clerk and you should walk out with an answer.
If you are just curious, this should suffice. If there is a dispute, get legal advice from an attorney. A survey will be your definitive answer, good, bad or otherwise.