Refers to the country Iceland. The katakana form is standard; the ateji spelling 愛斯蘭 is historical and not used in everyday writing.
Iceland is a country of volcanoes and glaciers.
Ateji (phonetic kanji) spelling; rarely used in modern Japanese.
From English 'Iceland', via Dutch 'IJsland' or directly from English. The ateji spelling 愛斯蘭 is a phonetic rendering using kanji.