The plateau runs north to south between the Geer and the Meuse, from Maastricht down through the Belgian municipality of Riemst almost to Liege, defining the topography of a triple border zone between Flanders, Wallonia, and the Netherlands. The hill is modest by mountain standards, peaking at 171 metres above sea level. What makes it geologically peculiar is its composition: chalky limestone of the Maastricht Formation, studded with flint nodules and threaded with fossils of sea urchins, clams, and belemnites. Since the 1930s the hill has been split in two by the Albert Canal, which cuts a ditch 1,300 metres long and 65 metres deep through the ridge near the Belgian village of Lanaye. The Lanaye locks at the eastern end of the cut lift barges between the upper Meuse and the Rhine basin.

Humans have mined this hill since the Neolithic, digging out flint for tools, then quarrying chalky limestone for building stone and fertiliser. By the nineteenth century the underground network of mining tunnels ran for some two hundred kilometres beneath the plateau. Many of Maastricht's medieval churches are built of stone hauled out of these galleries. Locals call the stone mergel and the corridors grotten, though strictly speaking neither word is accurate; this is limestone, not marl, and the passages are man-made, not natural caves. The walls preserve graffiti from the late Middle Ages onward, drawings, prayers, names scratched by candlelight. Today guided tours of the surviving sections are one of Maastricht's main attractions. Bats overwinter in the cool dark. During the Second World War, the same tunnels served as air-raid shelters and as hiding places for art, including pieces evacuated from the Rijksmuseum.

On the Flemish slopes near Riemst, archaeologists have found traces of an Iron Age fortress. It is one of the strongest candidates for being Atuatuca, the stronghold of the Eburones that figures prominently in Julius Caesar's Commentaries on the Gallic War. The Eburones, led by Ambiorix, ambushed and destroyed a Roman legion in 54 BC, one of the worst defeats of Caesar's career. Dendrochronological evidence once seemed to rule the identification out, but more recent reviews have revived the idea. The medieval period left its own marks: the motte-and-bailey castle De Tombe on the western slope, the eleventh-century keep absorbed into the farmstead Lichtenberg on the northeast, the ruined Caestert in the Walloon municipality of Vise. Louis XIV's troops favoured the hill as a firing platform during the siege of Maastricht in 1673, which is why the fortress Sint-Pieter went up at the northern edge in 1702, looking down on the city it was built to protect.

The defining feature on modern maps is a great white scar on the northeastern flank: the ENCI quarry, operated by the cement company ENCI since the mid-1920s in the Dutch part of the hill. Over decades the quarry ate most of the mount's limestone, producing portland cement and a long-running controversy about industrial extraction in a protected nature area. In 2010 the parties finally agreed that the quarry would close by 2018. It did. What remains is a startling landscape of stepped chalk walls, lakes formed in the lowest cuts, and a spectacular staircase with viewing platforms zigzagging down the cliff face. Parts that were mined out decades ago are already returning to wildness.

Mount Saint Peter is a Natura 2000 protection area, and its limestone soil and warm south-facing slopes create a botanical hotspot unusual for the latitude. Several species of orchids reach their northern limit here, including the bee orchid Ophrys apifera, whose flower mimics a female bee well enough to fool the males that try to mate with it. The Dutch society Natuurmonumenten owns most of the Dutch side and uses a small flock of sheep to keep grassland open against invading scrub. Eurasian eagle-owls have settled in the abandoned quarry walls. A short walk from the centre of Maastricht delivers you to the seventeenth-century Slavante monastery ruins on the slope, a Saint Anthony chapel, an 1846 pavilion called Casino Slavante, and a view across the Meuse valley that has been painted at least since the seventeenth century, when Joris van der Haagen captured it in oil from almost this exact spot.