What steps can I take when I find public land marked as private?

Over the last few years I have come across a few spots that are marked private when in fact they are not private. Even got chased out of a spot that I knew was blm land?
Answer: 
If you come across public land that has been posted with no trespassing signs, please contact the government agency who administers the property.  This could be the Bureau of Land Management, US Forest Service or any other land management agency.
Answered on: 
Monday, January 4, 2016 - 4:32 PM MST