The typical asking rate per listing is in the $30's per square foot per year. The Riverhead region is going through a decrease in rates. In the last 3 months, the median rate decreased $2 per sqft per year. That's a 6% decrease in rent.
In the last 90 days, 1 listings have been listed, which means new listings 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 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 1,500 sqft. Most buildings in this area are around 1 stories. Most buildings in this market were built in 1990 and are Class B.