Most listings are in the $30's per square foot per year. The Portland region is experiencing a a rise in rates. In the last 3 months, the median rate increased $9 per sqft per year. That's a 37% increase in rent.
In the last 90 days, 44 listings have been posted online, so you'll want to check back regularly for new listings. About 84% of the office spaces in the Portland are subleases, so you might be able to find a shorter term or below market rent. 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 2,160 sqft. Most properties in this area are approximately 3 stories. Most buildings in this area were built in 1900 and are Class B.