Most listings are in the $70's per square foot per year. The Portsmouth region is going through a a rise in rates. In the last 3 months, the median rate rose $57 per sqft per year. That's a 264% increase in rent.
In the last 90 days, 16 listings have been posted online, which means new availabilities are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 7,390 sqft, there are still 0 new availabilities below 2,000 sqft. Most properties in this area are close to 2 floors. Most buildings in this region were built in 1978 and are Class C.