immemorial

/ˌɪməˈmɔːriəl/

im·me·more·ial

BrE /ˌɪməˈmɔːriəl/

NAmE /ˌɪməˈmɔːriəl/

(formal or literary)

that has existed for longer than people can remember

an immemorial tradition

My family has lived in this area from time immemorial (= for hundreds of years).