Most listings are in the $20's per square foot per year. The Herndon submarket is seeing a a rise in rates. In the last 3 months, the median rate went up $29 per sqft per year.
Compared to the rest of the Washington D.C. market, the Herndon region has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 15 listings have come on the market, which means listings most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 53% of the available space in the Herndon 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 on the market, so finding a space for a small business might be tough.
Even though the median size is 3,590 sqft, there are still 0 spaces below 2,000 sqft. Most properties in this market are close to 1 stories. Most buildings in this market were built in 1987 and are Class B.