Most listings are in the $20's per square foot per year. The Loudoun County region is going through a a boost in rates. In the last 3 months, the median rate increased $29 per sqft per year.
In the last 90 days, 34 listings have been posted online, which means listings might be leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 385% of the available space in the Loudoun County are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 market were built in 2000 and are Class A.