Riverbend Park is north (upstream) of Great Falls National Park. It's a pretty small area, you can climb all the routes here in a day. The climbs are short (around 30 ft), some are fun, but nothing too hard. The crag is more vertical near the ground and it gets slabby as you go up, so the cruxes are generally near the start. It's not an area that warrants repeated visits, but on a busy summer weekend, you may want to give it a try to get away from the crowds at Great Falls.
To get there, park at the northernmost parking lot at Great Falls NP. Take the riverside trail upstream until you get to Riverbend Park, the crag is just a little bit further. You will see a 30-foot cliff on your left hand side as you're walking north, this is it.