On average, listings lease in the $40's per square foot per year. The Mount Vernon submarket is going through a decrease in rates. In the last 3 months, the median rate fell $3 per sqft per year. That's a 6% decrease in rent.
In the last 90 days, 5 listings have come on the market, which means leases are probably going fast. You'll want to be prepared to make an offer immediately. About 180% of the listings in the Mount Vernon are subleases, so you might be able to snag a great spot on a short term. 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 1,400 sqft. Most properties in this area are approximately 3 stories. Most buildings in this area were built in 1950 and are Class A.