Carthew Lakes

Overview

Two high‑alpine lakes tucked in a glacially carved hanging valley, Carthew Lakes are the showpiece of the Carthew–Alderson route. Expect stark peaks, colorful argillite scree, and turquoise water framed by big “Crown of the Continent” views. It’s remote and feels wild despite the trail’s popularity.

What You’ll See

• Upper and Lower Carthew Lakes in a broad, rocky basin below Carthew Ridge and Summit
• Snow patches often lingering into August, wildflowers in late summer, and sweeping vistas toward distant peaks
• Striking red/green argillite underfoot and open slopes, with sections of previously burned forest on the approach adding to the contrast

Wildlife

• Marmots commonly sunning on talus near the lakes
• Mountain goats are often spotted on the steep cliffs as you descend toward Alderson Lake
• Alpine birdlife along the ridge; large mammals are less commonly seen right at the exposed lakes

Getting There & Logistics

• The lakes sit mid‑route on the point‑to‑point Carthew–Alderson hike between Cameron Lake and the Waterton townsite (part of the Great Divide Trail corridor)
• Most hikers organize transportation with a shuttle or two‑car setup and start from the Cameron Lake side
• Plan for a full day (roughly 6–9 hours for the traverse) and bring everything you need—there are no services at the lakes

Conditions to Expect

• Above treeline: little shelter from sun, wind, or sudden storms
• Early season and even midsummer can mean snow crossings and loose scree—hiking poles help
• Mosquitoes can be present earlier in the season near lower elevations

Fishing

• The lakes are fishable, but you must carry the appropriate fishing license and treat any water you use

Best Time to Visit

• Prime season is July–September, when most snow has melted and the route is fully passable
• Start early for cooler temps and a quieter feel; the area sees plenty of hikers in peak season
• Photographers get great contrast on clear days, with lingering snowfields accenting the turquoise water

On‑site Facilities

• None. No trailhead, restrooms, picnic tables, or camping at the lakes (nearest backcountry campground and outhouse are farther along at Alderson Lake).