USGS GeoPDF Locator Map Does USNG
The Google-powered USGS GeoPDF locator map dynamically displays coordinates associated with mouse location, displaying both lat/long and USNG. It's the first time I've seen the dual coordinate display on a web map. TerraGo HQ is at 16S GC 3500 5400. USNG is handy to use with USGS quad sheets and lets you work in linear units rather than lat/lons. Cool!