See the map here: https://www.ww2history.eu/from-d-day-to-paris/3669-d-day-plus-56-68.html
An American corps led by two armored divisions sped past Avranches and quickly overran Brittany, forcing the few German units there not already committed to Normandy into fortified coastal enclaves.
Further mobile columns pushed through the Avranches gap and swung south and east, some hooking towards Argentan to entrap Germans remaining in Normandy while others pushed towards Le Mans for a deeper penetration.
A desperate German counterattack at Mortain attempted to break through to the sea and split the Allies in two, but was turned back after fierce fighting.
