ZitatDoes anyone know a source where one can online query the ownership status of an area in the US?
I agree with Volker, the situation is very complicated on Navajo land, even if you buy an official permit at a Navajo Visitor Center or Chapter House.
Each Navajo family (and even each Navajo) decide if they accept visitors or not on "their" land (in fact they have not the property of these lands, it belongs to the Navajo Reservation which gives a family the right to use it).
For example, the Navajo leaving near the Hopi Clown accepted me to go to this place only because I had a permit (that he verified very closely) but also because I was able to talk with him about people of his family that were leaving there before. But he asked me to not disclose this location because he didn't want more people there even with a permit. The other Navajo who was very angry against us in 2009 ('"I will call my brothers to beat you") told us "I don't care any permit given by these Navajo guys from Cameron, here it is my land !". The Navajo who is leaving near White Mesa Arch used to accept visitors with a Navajo permit but he doesn't accept any more since last year, as this place became more popular.
In a general way, if there is a remote place in the Navajo Reservation that is still confidential with very very few visitors a year, you have a chance to get there with a permit and a respectful attitude with the locals. But if this place become popular (for example because somebody published the coordinates on the web) you can be sure that it will be very soon forbidden for everybody (that's exactly what happened to the Hopi Clown). So, people should think twice (or more) before publishing this kind of coordinates on the web !