Most listings are in the $20's per square foot per year. The Eastchester region is experiencing a decline in rates. In the last 3 months, the median rate fell $9 per sqft per year. That's a 25% decline in rent.
In the last 90 days, 6 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 33% of the listings in the Eastchester 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,960 sqft. Most properties in this region are around 3 stories. Most buildings in this area were built in 1970 and are Class A.