New Hampshire Route 111's western terminus is at the Massachusetts state line at the southeastern corner of the town of Hollis, New Hampshire. The roadway continues to the south as Massachusetts Route 111. Eastbound NH 111 continues in a mostly northeasterly direction along Runnels Bridge Road, crossing the Nashua River about 1/2 mile from the border, and passing the Overlook Country Club. Immediately after the Nashua River bridge, NH 111A leaves to the east along Groton Road. NH 111 crosses into the city of Nashua, and the name changes to West Hollis Street. In Nashua, the route parallels the Nashua River's south bank, moving through the suburban southwestern quadrant of the city. At U.S. Route 3, a complex interchange involves the U.S. Route 3 freeway, NH 111, the eastern terminus of NH 111A (now called Main Dunstable Road), and several local streets. Leaving the interchange, NH 111 splits into two one-way streets, with West Hollis Street carrying westbound 111, and Kinsley Street carrying eastbound 111. St. Joseph Hospital lies along this stretch. After crossing Main Street and passing Nashua City Hall and Southern New Hampshire Medical Center, the two one-way streets merge again onto East Hollis Street. Going through an industrial part of East Nashua, still following the south bank of the Nashua River, NH 111 crosses the twin-span Taylor Falls/Veterans Memorial bridges over the Merrimack River (known locally as the Hudson Bridge) into the town of Hudson.