The New Haven and Northampton Railroad (founded as the New Haven and Northampton Company, also known as the Canal Line) was a railroad originally built alongside a canal between 1847 and 1850 in Connecticut. Leased by the New York and New Haven Railroad from 1849 to 1869, the railroad expanded northwards to Massachusetts and its second namesake city in 1859. Upon the end of the lease in 1869, the company expanded further into Massachusetts, reaching as far north as Shelburne and Turners Falls.
After a fight for control of the company by several other railroads in the 1880s, the New Haven and Northampton was leased by New York, New Haven and Hartford Railroad in 1887. The company continued to exist as a lessor until October 26, 1910, when it was formally merged into the New Haven system. In the 20th century, much of the line was gradually abandoned, though two portions continue to see freight service as of 2021. The vast majority of the abandoned line is now part of the Farmington Canal Heritage Trail, with the right of way owned by the State of Connecticut.