Montagne des Lignes, Mountain summit in Estrie, Canada

Montagne des Lignes is a mountain summit in Estrie that reaches 904 meters and features forested slopes mixed with rocky outcrops. The peak is marked by a narrow ridge at the top where walkers gain open views in multiple directions.

The mountain's name comes from the English word "line", referring to the Canada–US border that crosses its summit area. The border pass at 720 metres has long been used as a crossing point, reached from Quebec by Route 257 and from New Hampshire by US Route 3 through Pittsburg. The summit itself lies at the northern end of the White Mountains.

The name comes from the English word "line", meaning the Canada–US border, which runs across the mountain. The border crossing sits in a 720-metre col reached from Quebec by Route 257 and from New Hampshire by US Route 3 through Pittsburg. South of the line lies the Connecticut Lakes State Forest, where the Connecticut River rises.

Access is via the SF1 trail starting from the Chartierville rest stop, following an ATV track that leads toward the border. The terrain becomes steeper and more rocky as you approach the summit, especially along the ridge section.

From the narrow ridge at the summit, Third Connecticut Lake in New Hampshire is visible along with the mountain ridges beyond it. This southern view makes the peak a notable vantage point for seeing into the neighboring state.