The National Map
The US Geological Service hosts The National Map on their website, where a great deal of information is freely available. The national map itself has many layers that can be turned on and off, making various types of highways, railroads, or pipelines appear or disappear with a click.
They call it The Nation's Topographic Map and we used it to get the claimsite coordinates from their legal description.
The website has been under construction of late, so we can't say for sure how to work any feature, but in the past it has been a good resource for prospectors and prospecting.