▁Bernard ino ▁County . ▁In ▁ 1 9 7 3 , ▁Am boy ▁Cr ater ▁was ▁designated ▁the ▁Am boy ▁Cr ater ▁National ▁Natural ▁Land mark . ▁ ▁Location ▁The ▁cr ater ' s ▁location ▁is ▁ ▁south west ▁of ▁the ▁town ▁of ▁Am boy ▁and ▁the ▁Route ▁ 6 6 - National ▁Tra ils ▁Highway . ▁The ▁Bull ion ▁Mountains ▁are ▁to ▁the ▁west , ▁and ▁the ▁Br istol ▁Mountains ▁to ▁the ▁n ortheast . ▁ ▁Description ▁This ▁c inder ▁cone ▁is ▁estimated ▁to ▁be ▁ 7 9 , 0 0 0 ▁years ▁old ▁(+ /- ▁ 5 , 0 0 0 ▁years ) ▁and ▁was ▁formed ▁in ▁layers ▁of ▁mostly ▁ves icular ▁p ah oe ho e ▁during ▁the ▁Ple ist oc ene ▁ge ological ▁period . ▁The ▁interior ▁has ▁a ▁la va ▁lake . ▁L ava ▁flows ▁as ▁old ▁as ▁Am boy ▁Cr ater ▁itself ▁blank et ▁the ▁surrounding ▁area . ▁The ▁most ▁recent ▁er u ption ▁was ▁approximately ▁ 1 0 , 0 0 0 ▁years ▁ago . ▁ ▁The ▁cr ater ▁is ▁ ▁above ▁sea ▁level , ▁about ▁ ▁above ▁the ▁surrounding ▁bas alt ▁la va ▁pla ins . ▁The ▁scen ic ▁and ▁solit ary ▁Am boy ▁Cr ater ▁was ▁a ▁popular ▁sight ▁and ▁stop ▁for ▁travel ers ▁on ▁U . S . ▁Route ▁ 6 6 ▁in ▁California ▁before ▁the ▁opening ▁of ▁Inter state ▁ 4 0 ▁in ▁ 1 9 7 3 . ▁Other ▁than ▁a ▁stretch ▁of ▁U . S . ▁Route ▁ 6 6