A ~ journey or route goes from one side of a continent to the other. In American English, ~ usually means from one side of the United States to the other.
...in mid-nineteenth-century America, before the ~ railroad was built.
ADJ: usu ADJ n
TRANSCONTINENTAL
Meaning of TRANSCONTINENTAL in English
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012