Most listings are in the $20's per square foot per year. The Lorton region is going through a a boost in rates. In the last 3 months, the median rate went up $26 per sqft per year. That's a Inf% rise in rent.
Compared to the rest of the Washington D.C. market, the Lorton region has lower rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 1 listings have been listed, which means 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 150 sqft. Most properties in this region are around 1 floors. Most buildings in this region were built in 1979 and are Class A.