The loop at the park is almost exactly 1 mile, and it is fairly steep to my eyes. However, it only represents 118 feet of elevation gain, packed into 0.4 miles, an average of 295 feet of gain per mile--which ain't much. Feels like it, though. I was able to do the loops in about 11 minutes, which is just a minute off my normal pace, so it wasn't too bad.
HOWEVER, this really killed my left foot. I have a chronic case of plantar fascitis, which is the vampire bite of running--it never really seems to go away, and it can be so painful you can't really walk. Today really flared it. So I won't be doing hill repeats for a while, as this injury is what kept me from running for 2 years.
The ChiRunning website has some tips, which I intend to incorporate. Can't let this running streak be broken by a silly injury.