The Northampton and Peterborough Railway was an early railway promoted by the London and Birmingham Railway (L&BR) to run from a junction at Blisworth on the L&BR main line to Northampton and Peterborough, in England. The construction of the line was authorised by Parliament in 1843 and the 47 mile line opened in 1845. The line largely followed the river Nene, and for economy of construction, it had many level crossings with intersecting roads, rather than bridges. In 1846 the L&BR joined with other companies, together forming the London and North Western Railway (LNWR).