Hunting with a GPS to search for State, BLM, National Forest Etc.

GPS is a tool, a powerful tool, that will assist you when hunting, but does not replace the reality of what is on the ground.  If a property is signed as No Trespassing or Private you must respect that until you learn more.  It is difficult and time-consuming to keep property information up-to-date, especially in Idaho where there is no single statewide property layer and no standing agreement between counties, state and federal agencies to share these data (more info).  Finally, GPS is not a perfect system.  There is error associated with every location, often only feet or inches, but sometimes far more significant depending on time of day and conditions.  With this background in mind, here is some specific answers to your questions. 1) What do I do if I encounter land that is posted, but my GPS says it is State, BLM, or NF? This land management information in your GPS, like the land management layer in the Huntplanner MapCenter, is most likely based on the BLM Surface Management Layer.  This layer is updated constantly, but continually out of date, especially the copy in your GPS Unit which was made sometime back before being sold and packaged in your GPS Device.  It has no way or receiving updates.  So if it is posted, I would consider it private.  If you have specific questions about a location, it is best to approach your local county assessors office who is ultimately responsible for this information. 2) What do I do if confronted by a property owner that says the land I am on is his, when my GPS says otherwise? Again, take the property owner at their word until you learn otherwise from your local county assessor.  In addition to out of date information in your GPS Device, there are also many reasons why your GPS Unit, though it claims an accuracy of several feet may be off by hundreds of feet or even miles.  Some of these factors include clouds, trees, topography or even time of day when satellites may be low on the horizon or not available.  It takes three satellites high in a clear sky to get a reliable fix.  If you read the owners manual on your GPS you can learn how to tell how accurate a positional fix is *estimated* to be at a given time. 3) Is all State, BLM, and National Forest legal to hunt on? Most BLM and National Forest land are open to hunting with the exception of some specific areas closed for public safety (e.g. Redfish Lake Public Beaches).  State land varies by agency.  Fish and Game owned lands are open to huning while many State Parks are not. 4) If I am trying to gain access to State, BLM, or National Forest and there is road access shown on the GPS. Can a property owner keep me from accessing that land through his land? The short answer is yes.  However if it is a publicly owned road they may not block the roadway.  A road on your GPS *does not* mean it is a public roadway.  Public roadways include federal, state and county routes as well as National Forest roads with a forest road number.  There are many isolated tracks of state and federal land that are only accessible via private property.  In fact, there are several Access Yes properties which Fish and Game leases solely to open access to public lands.