What poetic nickname for Ireland is often used on St. Patrick's Day?

Ireland’s poetic nickname, especially familiar on St. Patrick’s Day, is the Emerald Isle.

The nickname refers to Ireland’s famously green landscape: grasslands, hedgerows, hills and a damp Atlantic climate give much of the island a lush appearance. “Emerald” also evokes the deep green gemstone, making the phrase both a visual description and a poetic expression of affection for the country.

The wording became established in 19th-century Irish nationalist and literary culture. It is often linked with the poem “When Erin First Rose” by William Drennan, whose use of emerald imagery helped popularise the expression. “Erin” itself is a poetic English name for Ireland derived from Éire.

The Emerald Isle is a nickname, not Ireland’s official name. “Celtic Isle,” “Shamrock Shore” and “Green Land” may sound plausible because they refer to Irish symbols or scenery, but they are not the standard poetic nickname. The shamrock is an important national symbol, while the emerald image describes the island as a whole.