OscarC wrote:troyv is correct. I have good luck just web searching "<county name> <state> GIS", and it will usually pull up a local government page that will allow you to access an interactive GIS map. Generally they are used for property searches and tax information, and that includes the property address.
So far, at least in Minnesota, this has given me good addresses in 90% of the counties I try. Most of the time they are also a good reference for roads, road names and city/township borders, including newer development that doesn't appear on Google Maps or other sources. Some counties just don't do it online though so then you have to use maybe a post office listing or something else. Unfortunately the maps are not standardized and some are easier to use and/or more informative than others.
That's not entirely consistent state to state and even county to county.
You also have to look out for subtle definition issues. For example, lot number does not always equate to house number, and if the county database or map shows lots without addresses, you may end up transferring very bogus information onto the map.