Such as Hawaii, which was a country when they became a territory. First and foremost your will need your Land Patent. It will tell you what has been set down as your rights to your land. These rights are between you and the Federal Government and no other third party. It sounds too good to be true, but the background work for this is in any law library in the United States.
Land patents come from several different places.
The original colonies land patents came from the corresponding country of control. The U. S. Government honors those patents because of the treaties. Those patents are still in force as are the patents issued by the U.S. Government today. All land patents are forever. The patents that were issued to the colonies can be found in the corresponding state archives.