NHLs are designated by the United States Secretary of the Interior because they are:
ɛ n eɪ t̠ʃ ɛ l z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY d ɛ z ɪ ɡ n eɪ t ɪ d WORD_BOUNDARY b aɪ WORD_BOUNDARY ð ə WORD_BOUNDARY j uː n aɪ t ɪ d WORD_BOUNDARY s t eɪ t s WORD_BOUNDARY s ɛ k ɹ ə t ɹ i WORD_BOUNDARY ʌ v ð ɪ WORD_BOUNDARY ɪ n t ɪ ɹ i ə ɹ WORD_BOUNDARY b ɪ k ʌ z WORD_BOUNDARY ð eɪ WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY