On average, listings lease in the $20's per square foot per year. The New Castle County region is experiencing a an increase in rates. In the last 3 months, the median rate went up $3 per sqft per year. That's a 11% increase in rent.
In the last 90 days, 209 listings have been listed, so you'll want to check back regularly for new listings. About 1% of the available space in the New Castle County are subleases, so you will probably have to consider a longer term 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 2,280 sqft. Most properties in this market are around 2 stories. Most buildings in this area were built in 1986 and are Class A.