Jurupa is a relatively short hike, but what it lacks in length, it more than makes up with steepness! I picked up a use trail from Jurupa Park on the edge of Fontana, and I followed it up, up, and up the steep hillside. The hike is about, or a little more than, 2 miles r/t with about 1,100' gain! It is very popular with the locals, so expect plenty of company on this one, and many of the boulders are painted with interesting graffiti! On the use trail I used, there are even a few class-2 sections, so you'll get a great workout! The summit is a very broad, flat plateau with some inspirational views all around the Inland Empire. Beware, going back down is a little sketchy as the soil and rocks can be slippery!! Also beware of some Poison-Oak on the edge of the trail in a few spots!!