• 峠とうげ — mountain pass
• 峠道とうげみち — mountain road; pass road
• 峠とうげを越こえる — cross a mountain pass
• 峠とうげを下くだる — go down a pass
• 山やまの峠とうげ — a pass in the mountains
• 人生じんせいの峠とうげ — life’s turning point (figurative)
• 峠とうげを過すぎる — be past the peak / worst is over

峠（とうげ） originally means a mountain pass — the point where you finish climbing and begin going down. From this image, 峠を越える came to mean reaching a turning point or peak and moving past it. It’s often used figuratively for difficult situations that are finally on the way to improvement.