Most listings are in the $20's per square foot per year. The Jefferson Park region is going through a a rise in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 7% rise in rent.
Compared to the rest of the Chicagoland market, the Jefferson Park region has higher rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 3 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 680 sqft. Most properties in this market are around 1 floors. Most buildings in this market were built in 1950 and are Class A.