The Pittsfield and North Adams Railroad was a railroad based in northwestern Massachusetts. It was chartered in 1842 and was purchased by the Western Railroad of Massachusetts before construction was finished in 1846, then acquired by the Boston and Albany Railroad in 1870, only to face a gradual demise between the 1960s and 1990. It ran 18.539 mi (29.836 km) from North Adams Junction in Pittsfield to North Adams, where it connected to the Troy and Greenfield Railroad, an affiliate of the Fitchburg Railroad.
The Pittsfield and North Adams was incorporated on March 3, 1842, by special act of the State of Massachusetts. The original owners of the P&NA developed this corridor with the goal of extending the Housatonic Railroad north to Rutland, Vermont. It was organized December 18, 1845 and opened for operation on December 1, 1846. Before the tracks were under construction, the company was acquired by the Western Railroad of Massachusetts, which allowed the Housatonic to use the line until the Western Railroad became part of the Boston and Albany Railroad (B&A) on November 2, 1870, as their North Adams Branch. Mineral traffic developed on the line and a number of limestone operations went into business. The New York Central Railroad took over the B&A in 1900, and upgraded the line, although it allowed the B&A and its branches to operate under its old name. Brochures and schedules of the New York Central made the North Adams Branch seem as if it were a segment of the Harlem Division, despite the fact that the aforementioned line terminated at Chatham Union Station in New York. Some brochures with this extension actually pre-date the purchase of the B&A by NYC.