Most listings are in the $20's per square foot per year. The North Riverside region is going through a an increase in rates. In the last 3 months, the median rate rose $21 per sqft per year.
In the last 90 days, 3 listings have been posted online, which means new availabilities are probably going fast. You'll want to be prepared to make an offer immediately. 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 1,500 sqft. Most buildings in this market were built in 1936 and are Class B.
Not much of the real estate is used for commercial space, so it might be hard to find office space. Utilities is the dominant industry in this area. Most of the residents of North Riverside work from home. Commuting approximately 30 minutes a day is the norm for those who opt to reside in this part of town.