In my freshman year we went up to 9 miles.
We had one day in my sophomore year that we went 14 miles, though this was on a saturday and we brought water in our coach's car.
Prepare yourself by being able to run up to 4 miles with a single stop at the 2 mile mark to stretch some more and do some sprints. Before I quit out of hatred of waking up at 5 am to run during summer, we would run a couple miles up into the hills, then do a bunch of repeats; that's sprinting a certain distance, and jogging at a normal pace back down. Then you have about two seconds to really breathe, and you're sprinting back up the hill. It took a couple weeks to get used to in my freshman year, but most of us got used to it.
Practice is slower pace though, unless you intend to kick *** during meets. Meets are a standard 3 miles in which a good time is under 18 minutes. I barely broke 20 at my best before I started ditching the meets.