The Caloris Montes (Latin for Heat's Mountains) are a range of mountains on Mercury. 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). The range consists of numerous rectilinear massifs 1 to 2 km high and about 10 to 50 km long, mostly elongated radially from the center of the basin and separated by hackly-floored, radial troughs and gouge-like structures. The surfaces of the massifs are hackly. 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. The range marks the crest of most prominent ring structure around Caloris. The type area is the region near 18°, 184.5° (FDS 229). It is thought to be composed of uplifted prebasin bedrock covered by deep-seated late ejecta from Caloris. The inner boundary is approximately the outer limit of crater excavation.