BLM Maps for Android have recently become available for 12 western states. These maps primarily show the boundaries of BLM land, and secondarily show boundaries between state, federal and public land.
The product is available as an overlay that displays boundaries on your existing maps. You can purchase it by going to "Purchasing Add-ons" deep in the menu. It has quickly become a popular product. Below are some comments about the source of the data, its accuracy, and some disclaimers.
BLM data comes from the State Bureau of Land Management units. This is more accurate and recent than what the National BLM office would have, but less accurate than what your county asessor might have at the hall of records.
We can give no warranty, express or implied, as to the accuracy of the data, because the BLM itself won't do that. The data is subject to errors both by the BLM and other organizations that share data with the BLM.
While many of you want to use this data to stay off private land, comply with the law, and avoid getting shot, we cannot guarantee its reliability for this purpose. Think of it as a step in the right direction.
To help out, we are posting links to the sources for the data at each state agency. The link has notes about the data, where it came from, how it evolved.
If you do find a discrepancy in the data, please contact the people listed at the link. They promise continual improvement.
Montana (covers parts of North and South Dakota).
Land ownership (Statewide)