If you visit Glacier National Park, the Grinnell Glacier hike is a must do! It is a moderately strenuous 11.6 mile round trip with over 1,800 feet of elevation gain. You can cut out 3.4 miles of the hike by taking two classic wood boats across Swiftcurrent Lake and Lake Josephene. Book them way ahead to get a spot. The hike opens fully towards the end of July. Otherwise, you may not be able to go all the way due to snow. Check the NPS site for updates.
Craig and I went on the ranger led hike and had a great time. It was tough climbing the first part of the hike, and we were glad to have poles going up and back down. Our ranger David stopped every so often to give the group a rest and to give slower hikers a chance to catch up. We learned a lot about the geology of the park, saw three glaciers, amazing wildflowers, walked through waterfalls, saw wildlife like Bighorn Sheep and 1.5 billion year old Stromatolites.
Take plenty of water on the hike and wear a hat and good hiking shoes/boots. You may want to order a box lunch from your hotel the night before and take a small soft-sided cooler with you. There is a picnic area along the way with benches and pretty clean pit toilets. It is a hard hike, but so worth the effort. It is probably my favorite hike I have done so far. It is hard to show how enormous Grinnell Glacier is with pictures. It is also amazing to see how far it has receded. Please go and experience it while you still can!