We still maintain Loran C[0]. Interesting to note receivers have been developed to grab the radio signal from all available stations, up to 40, and triangulate location with eLoran. It's a nice to have as backup to GPS however I'm not sure if it is effective against jamming or spoofing. So, the navy still teaches celestial navigation to officers. [1]

EDIT: Apparently Loran C was discontinued in 2010.

[0]https://en.wikipedia.org/wiki/Loran-C [1] https://www.stripes.com/news/break-out-the-sextant-navy-teac...