2 spaces now available! Anchored by Market Basket, Marshall's, Home Goods and 4 distinctive restaurants situated on 31 acres off I-495 at Exit 83 (formerly Exit 32), Cornerstone Square sets the standard in the region for distinctive architecture, dining, shopping and professional services. I-495 Exit 83, Rt. 110 & Boston Rd, with 4,000 ft. of frontage, in the heart of the Westford, MA commerce region