virgin soil; uncultivated land
Refers to land that has never been cultivated or developed, often used in agricultural or geographical contexts.
There is still a vast area of uncultivated land in that region.
開墾地 refers to land that has been cleared and cultivated, the opposite of 未開墾地.
未開地 is a broader term for undeveloped or uncivilized land, not necessarily agricultural.
Compound of 未 (mi, 'not yet') + 開墾 (kaikon, 'cultivation, reclamation') + 地 (chi, 'land').