How can I find the last Synced location for my phone (which is now dead/off)? I'm using Google's [Device Manager][1] to find my phone. It shows the last sync time as yesterday but won't show me WHERE that was.

(I'm sure my phone battery got too low and it turned off)

Device Manager shows:

Location unavailable 

Last online January 29, 2017 (yesterday)

Seems like I should be able to find the last place it sync'd but I see no option for that.
Google's Device Manager does not store location. It will send a location request to your device, which if turned on with a network connection and location services enabled, will respond with its current location. 

If you have location history enabled, your location should show up in the Google Maps timeline.