 Ramba uchiverenga ndima ino - Kuwedzera kwenyika kupfuura North America kwakatanga muna 1856 nekupfuura kweGuano Islands Act, zvichikonzera kuti zviwi zvidiki uye zvisina vanhu, asi zvakakosha mune zvehupfumi, muPacific Ocean neCaribbean Sea zviitwe. Zvizhinji zvezvikumbiro izvi pakupedzisira zvakasiyiwa nemhaka yezvikumbiro zvinokwikwidzana zvinobva kune dzimwe nyika kana kuti guano yakave ichibviswa. Kuwedzera kwePacific kwakaguma nokubatanidzwa kweHawaii muna 1898, pashure pokuparadzwa kwehurumende yayo makore mashanu apfuura. Alaska, kuwanwa kukuru kwokupedzisira muNorth America, yakatengwa kuRussia muna 1867. 