The typical asking rate per listing is in the $20's per square foot per year. The Riverside submarket is going through a a boost in rates. In the last 3 months, the median rate increased $25 per sqft per year.
Compared to the rest of the Chicagoland market, the Riverside submarket has greater rates, and you'll need to make a great offer to be in this hot region.
In the last 90 days, 1 listings have been posted online, which means listings might be going fast. You'll want to be prepared to make an offer immediately. About 100% of the available leases in the Riverside are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,340 sqft. Most buildings in this area were built in 1871 and are Class A.