[1] Formerly the town was renowned as a centre of pearl fishing, mentioned in the 2nd-century CE Periplus of the Erythraean Sea.

[2] Mannar is known for its baobab trees and for its fort, built by the Portuguese in 1560 and taken by the Dutch in 1658 and rebuilt; its ramparts and bastions are intact, though the interior is largely destroyed.

Visually, the modern town is dominated by its churches, Hindu temples and mosques.

Mannar has a tropical savanna climate (Köppen: As)[4] with warm to hot temperatures and a modest amount of rainfall.

Mannar experiences a distinct wet season from October to December, and the rest of the year is fairly dry.