First try to locate your property pipes. Knowing the dimensions of your lot and measuring from the existing property pipes is a relatively accurate way of establishing your lot lines. If your neighbor has a property pipe, you could also use that pipe to assist in locating your lot boundaries. Be sure you have permission from your neighbor to do this. You may have to hire a surveyor to re-establish your lot lines if there are not enough property pipes present or if you cannot find the pipes.
The property line along the street usually coincides with the road right-of-way. The zoning office does not have a county surveyor so if you are not sure where your lot lines are, you will have to hire a surveyor.