Tracking a Assaultron in Appalachia? The Archive logs 3 spawn locations for it across Cranberry Bog, Toxic Valley, and Savage Divide. Server population and active events shift the odds, but these are the spots the field notes keep returning to.
Several patrol the perimeter walkway just west of the station, and the whole robot-choked city is your best all-purpose Destroy a Robot farm. Skip Mayor for a Day if you want them hostile — that quest turns every Watoga bot passive.
Angry robots pack the underground works, sharing the site with Super Mutants — a closer option than Watoga for a quick Assaultron kill.
White-painted Whitespring Assaultrons patrol the grounds and interior as security. Passive until provoked, so fire first. Cripple the legs and back off — they detonate on death.