 A ring of coastal mountains surround low plains at the centre of the island . The highest of these is Carrauntoohil ( Irish : Corrán Tuathail ) in County Kerry , which rises to 1 @,@ 038 m ( 3 @,@ 406 ft ) above sea level . The most arable land lies in the province of Leinster . Western areas can be mountainous and rocky with green panoramic vistas . The River Shannon , the island 's longest river at 386 km ( 240 mi ) long , rises in County Cavan in the north west and flows 113 kilometres ( 70 mi ) to Limerick city in the mid west . 
 A ring of coastal mountains surround low plains at the centre of the island . The highest of these <a href='drop_aux' title='1'><mark>is</mark></a>Carrauntoohil ( Irish : Corrán Tuathail ) in County Kerry , which <a href='uninflect' title='2'><mark>rises</mark></a> to 1 @,@ 038 m ( 3 @,@ 406 ft ) above sea level . The most arable land <a href='uninflect' title='3'><mark>lies</mark></a> in the province of Leinster . Western areas can be mountainous and rocky with green panoramic vistas . The River Shannon , the island <a href='null_genetive' title='4'><mark>'s</mark></a>longest river at 386 km ( 240 mi ) long , <a href='uninflect' title='5'><mark>rises</mark></a> in County Cavan in the north west and <a href='uninflect' title='6'><mark>flows</mark></a> 113 kilometres ( 70 mi ) to Limerick city in the mid west . 
A ring of coastal mountains surround low plains at the centre of the island . The highest of these Carrauntoohil ( Irish : Corrán Tuathail ) in County Kerry , which rise to 1 @,@ 038 m ( 3 @,@ 406 ft ) above sea level . The most arable land lie in da province of Leinster . Western areas can b mountainous and rocky w/ green panoramic vistas . TdaRiver Shannon , thdasland  longest river at 386 km ( 240 mi ) long , rise in County Cavan in the north west and flow 113 kilometres ( 70 mi ) to Limerick city in thedad west .