Route 2A is a east–west state highway in Massachusetts. It exists in several sections of Massachusetts, mainly as parts of former Route 2 that have been moved or upgraded. Route 2A runs from Greenfield in the west to Boston in the east. It formerly extended to Shelburne Falls in Buckland in the west, but as of 2007, the route terminates at Interstate 91 (I-91) in Greenfield. Route description Route 2A begins at the rotary intersection with Route 2 at I-91 in Greenfield. It passes through downtown Greenfield before reconnecting to its parent route just west of the Greenfield-Gill town line. After a silent concurrency, Route 2A leaves Route 2 once more, passing through Orange and Athol. In Athol it passes the former northern terminus of Route 21, which was truncated to Belchertown after the creation of the Quabbin Reservoir. From Phillipston through Westminster, Route 2A weaves around its parent route, crossing it a total of six times with five exits of access off of Route 2. In Fitchburg the road is shared with several other routes as it passes through the northern half of town. Once in Lunenburg it has another short concurrency with Route 13 just north of the former Whalom Park before crossing into Middlesex County at Shirley. In Shirley, Route 2A passes north of Fort Devens into Ayer, heading into Littleton and crossing I-495 at exit 79 (formerly exit 30). It then turns south through Acton and into Concord before rejoining its parent route once more. As a silent concurrency, it passes south of the historic center of town and north of Walden Pond before splitting again. Route 2A then passes through the Minuteman National Historical Park just south of the Battle Road, the route taken by British troops between the Battles of Lexington and Concord. It then leaves the park, intersecting with I-95/Route 128 at exit 46 (formerly 30). The road passes south of Lexington's town center before winding into Arlington. In Arlington, the road begins a concurrency with U.S. Route 3 (US 3) which eventually joins the route to Massachusetts Avenue (Mass Ave). After US 3 leaves Mass Ave at Alewife Brook Parkway, Route 2A continues through the city of Cambridge, passing by Harvard Yard and through Harvard Square. Due to the one-way circulation patterns of the square, Route 2A follows Mass Ave in the westbound direction and a combination of Massachusetts Avenue, Brattle Street,