Detailed topographic maps of Mongolia are not so easy to find, but some thorough research led to a great resource for maps. This collection has maps for many regions that are difficult if not impossible to find elsewhere — while they may not be “current” in terms of roads and such, the topography of the land itself does not change, making the maps helpful for navigation and planning. The PDF maps can be downloaded for free and printed or used digitally.
Was able to obtain a set of 1:250,000 topos of the area of Mongolia we will be traveling in, and while the maps are old (from the 1980s), the topographical details will not have changed. We can use the maps for general planning purposes as well as for marking routes and other field notes when we are in-country.