On average, listings lease in the $10's per square foot per year. The O'Fallon region is experiencing a a rise in rates. In the last 3 months, the median rate increased $4 per sqft per year. That's a 25% rise in rent.
In the last 90 days, 21 listings have come on the market, which means office spaces might be leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,250 sqft. Most buildings in this area are approximately 1 stories. Most buildings in this region were built in 2001 and are Class A.