What is there to do in bloomingtin, IL
Assuming 4 people means a family with kids, you should check out Miller Park Zoo.
I recommend staying at either the Hyatt Place Bloomington/Normal or right across the street is the Bloomington-Normal Marriott Hotel & Conference Center. These are both in a great location right downtown near Illinois State University and walking distance to things nearby. The only downside is that you are a bit close to the train tracks if that bothers you.
If you happen to drive, there's a Tesla Supercharger also.
Also in that area is the Children's Discovery Museum.
If you happen to fly in, Central Illinois Regional Airport at Bloomington-Normal (BMI airport) is really nice because it's newer than many other airports and I think they still have free parking there too.
Oh, another campus in the area that's nice is Illinois Wesleyan University.
You should also know that Bloomington is the corporate headquarters for State Farm, so there's a good chance someone sitting in the restaurant might be on their lunch break from State Farm Plaza or State Farm Plaza South.
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Try eating at CoreLife Eatery. The #1 place for healthy dining. It is a beautiful place.