Arabia Terra is a large upland region in the north of Mars that lies mostly in the Arabia quadrangle, but a small part is in the Mare Acidalium quadrangle. It is densely cratered and heavily eroded. This battered topography indicates great age, and Arabia Terra is presumed to be one of the oldest terrains on the planet. It covers as much as 4,500 km (2,800 mi) at its longest extent, centered roughly at 21°N 6°E with its eastern and southern regions rising 4 km (13,000 ft) above the north-west. Alongside its many craters, canyons wind through the Arabia Terra, many emptying into the large northern lowlands of the planet, which borders Arabia Terra to the north. Source: Wikipedia (en)