Monte San Lorenzo, Mountain summit in Santa Cruz Province, Argentina.

Monte San Lorenzo, also called Monte Cochrane, is a 3,706-metre peak on the Argentina-Chile border in Patagonia, the highest mountain in Santa Cruz Province. Three large glaciers cover it: two on the Argentine side and the Calluqueo glacier in Chile. The Argentine glaciers show clear signs of retreat.

Alberto María de Agostini, a Salesian priest, reached the summit in 1943 at the age of 60, with Alejandro Hemmi, a Swiss, and Heriberto Schmoll, an Austrian, both long resident in San Carlos de Bariloche. The climb remained the mountain's first recorded ascent.

The Chilean name Cochrane comes from the town of Cochrane, the base from which climbers usually approach the mountain. The Argentine side lies in Río Chico Department, Santa Cruz Province, a few kilometres north of Perito Moreno National Park.

Access to the mountain is easiest through Perito Moreno, which offers accommodation and supplies for climbers. January through March provides the most favorable climbing conditions for those attempting the summit.

The Chilean glacier is named Calluqueo. The two Argentine glaciers show clear evidence of retreat, while the peak's Chilean name, Cochrane, comes from the nearby town of Cochrane, the usual approach base for climbers.