Maio is one of three flat islands in the archipelago, the other two being Sal and Boavista.
This island was an old volcano. It has been recorded that tests on marine sediments found on the island are deemed to be 190million years old.
Before Maio started trading in salt, the island was suitable for grazing cattle and goats, but as the vegetation slowly disappeared and numbers of cattle and goats on the island began to dwindle.
There are two large salt-pans, one in the northwest the other in the southwest. When the trade in salt and lime started, donkeys carried sacks of salt to boats that could ferry the salt to the bigger ships anchored out at sea. These ships in the early years transported this cargo to Europe, America, West Indies and Africa.
Some areas in the east have agricultural land and there are other areas of reforestation.