The Nashua, Acton and Boston Railroad (NA&B) was a railroad formed in 1871 to build a line between Nashua, New Hampshire, and Acton, Massachusetts. After opening in 1873, the railroad expanded to Concord, Massachusetts, and offered a commuter connection to Boston. It was leased by the Concord Railroad in 1876, with the lease later passing to the Boston and Maine Railroad in 1895. Most of the railroad line was abandoned in the 1920s, though a short portion in Nashua continued to be operated until 1980.