Windows 10 comes with a Maps app built in. It uses Nokia's nifty (and good!) Here Maps, and Microsoft even lets you download regions for offline perusal.
To download offline maps, just head to Settings — System — Offline Maps, or go to the Settings in the Maps app. (Or just search Offline Maps in the system-wide Search.) Maps lets you download by individual region. The files are understandably big — 300MB for New York state, for example.
There's no option to download to a particular folder, which is a shame — I'd have liked to have a set of world maps saved to a USB, ready to deploy whenever my roadtrip goes astray in a notspot. One weird quirk — maps won't download while the Maps app is open, which seems like a strange decision.
The map itself is pretty good. I've always liked the way Here maps feels close to a paper map, and it certainly retains that feel on Windows 10. Having the house numbers overlaid on buildings is nothing short of magical.