In the north the basin of the Cephissus and Lake Copais lies between parallel mountain-walls continuing eastward the line of Parnassus in the extensive ridge of Helicon, the "Mountain of the Muses" (5470 ft.) and the east Locrian range in Mts.
These ranges, which mostly lie close to the seaboard, form by their projecting spurs a narrow defile on the Phocian frontier, near the famous battlefield of Chaeroneia, and shut in Copais closely on the south between Coronea and Haliartus.
Though the Boeotian climate suffered from the exhalations of Copais, which produced a heavy atmosphere with foggy winters and sultry summers, its rich soil was suited alike for crops, plantations and pasture; the CopaIs plain, though able to turn into marsh when the choking of the katavothra caused the lake to encroach, being among the most fertile in Greece.
The first step towards the country's recovery was not until 1895, when the outlets of CopaIs were again put into working order.
She dwelt at the south-east corner of Lake Copais on a bald rocky mountain called Phicium (mod.