I've been to a lot of dogs parks between Minnesota and Georgia (driving with 2 big dogs means a lot of stops!). This dog park is the most beautiful dog park I have ever seen! It is very large (not the biggest i've seen, but it's bigger than 90%) and it is very well maintained. It has several different open areas for dogs to play and has natural barriers to keep dogs near their owners.
It does says you're supposed to have an Urbana Dog Park permit to use the park but there really isn't any way to enforce it. If I lived in the area I would gladly pay the annual fee, but I was passing through and stopped for 45 minutes so I guess I'm a rule-breaker. I picked up some other dogs' poops so I figure I did my due-diligence.
I went on a weekday around lunch and there were only about 5 dogs there.