They are a system of linear hills and valleys that extend more than 1000 km to the northeast from the mountainous rim of Caloris Basin in the Shakespeare quadrangle (H-3).
They are best developed along the inner edge of the basin where steep inward-facing scarps are common, grading outward into smaller massifs and blocks.
It is thought to be composed of uplifted prebasin bedrock covered by deep-seated late ejecta from Caloris.
It is generally believed that this type of lineated surface feature resulted from excavations by secondary projectiles when the large basins were formed and, possibly, fracturing and faulting of the planet's crust during the basin formation.
A gap is present in the Caloris Montes toward the southeast; its origin is unknown, but it is somewhat similar to the gap on the east side of the Imbrium Basin, where the mountain ring cuts the edge of the Serenitatis Basin.