On average, listings lease in the $20's per square foot per year. The Loudoun County region is experiencing a an increase in rates. In the last 3 months, the median rate went up $29 per sqft per year.
In the last 90 days, 34 listings have been listed, which means spaces are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 379% of the available leases in the Loudoun County 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.
The standard measurement for office space in this area is around 2,500 sqft. Most properties in this region are approximately 2 floors. Most buildings in this region were built in 2000 and are Class A.