Yes. The trails are quite steep in the beginning parts of each trail. Once you get up a ways they all level off a bit, but the start can be challenging. I would try the Oaks Bottoms nature area by the amusement park. Mostly flat and quite pleasant.
.The trail goes up the whole way to a lookout area at council crest,pretty steep all the way.
There are some steep hills as you go higher up the hill off Gibbs St. If you're around OHSU there one that goes down the hill with switch backs that make it a lot easier walk.
In general, yes there are a number of steep hills. The route you choose could ameliorate this, for example, for a short out and back (0.8 mile total) one could walk the Flicker Trail from the 12th Street entrance until it starts to drop steeply downhill.
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