Illecillewaet Campground is the close to the starting point for half a dozen different trails in Glacier National Park. If hiking in Glacier is your priority, I'd recommend spending at least one night here.
Set into a narrow valley, this frontcountry campground is on the compact side and has space for tents and smaller RVs only (less than 10m/33 foot). Sites are $24/night.
Operating on a first-come, first-serve system, it is usually possible to arrive during the early afternoon and secure one of the 60 sites. Park at an empty site and then walk to the Welcome Center on the main road to register.
There are flush toilets, campfires, kitchen shelters, potable water and food lockers in this campground but no showers.
The Illecillewaet Campground road is only accessible from Highway 1 when driving eastbound. When driving westbound (from Golden, Banff), you must pass the turnoff and continue another 1.5km to a marked U-turn route.
If you miss that, don't panic. Continue another 1.3km and there is another opportunity to turn around at the turnoff to the Loop Brook Campground.
A Parks Canada parks pass is required to camp at this campground ($22/vehicle with up to 7 people).