Belly River

The Belly starts at Helen Lake in Glacier National Park, Montana, crosses into Alberta near Chief Mountain inside Waterton Lakes National Park, and runs north past Mountain View, Hill Spring and Glenwood toward the Oldman. Parks Canada has closed the Belly and its tributaries inside the park because whirling disease was found there, so the open water starts at the park boundary south of Highway 5. This page covers about 60 km from there to the Highway 505 bridge at Glenwood. The 2026 Alberta regulation table lists rainbow trout, westslope cutthroat trout and mountain whitefish here, and leaves brook and brown trout out.

Read the Mountain View gauge, about 5 km below the park boundary. The Belly is a snowmelt river: it usually rises in May, runs high and coloured through June, often 15 to 50 m³/s (530 to 1,770 cfs), and drops back through July. In August it usually runs about 3 to 6 m³/s (105 to 210 cfs), low and clear. Above Highway 800 the river is open only from June 16 to August 31, so the real window is short: from the day it clears in July to the end of August. Expect stoneflies and caddis in July and hoppers and ants in August. Below Highway 800 the season runs on, catch and release, through October. The lower river changes at the diversion weir above Glenwood. Water from the Waterton Reservoir comes in by canal just above it, and the St. Mary canal takes most of the summer flow. The Glenwood gauge often reads only about 2 m³/s (70 cfs) in July and August, and it climbs again in October as the irrigation season ends.

Plan for three things. The upper river keeps nothing: every trout and whitefish goes back above Highway 800. Below it you may keep 2 trout over 35 cm (14") until August 31. Most banks are private ranch land, so start at a bridge or road allowance and stay below the high-water mark, or ask the landowner. And from just below the Highway 800 bridge, the Blood 148 reserve of the Kainai Nation lines the east bank, and near Glenwood it reaches both banks in places. You need the band council's permission to go on reserve land. Expect strong west wind, and in a hot, low summer the province can restrict fishing on ES1 streams to certain times of day.