The Erie Railroad had a long and complex web of predecessors in New York State. The corporate family tree below captures most, if not all of them.
- Erie Railroad (1895 – 1960), predecessors and associated companies, including
- Columbus and Erie Railroad (1905 – 1941)
- New York, Pennsylvania and Ohio Railroad (1880 – 1883)
- Atlantic and Great Western Railroad (1852 – 1880)
- New York, Lake Erie and Western Railroad (1878 – 1895)
- Erie Railway (1861 – 1878)
- Avon, Geneseo and Mt. Morris Railroad (1860 – 1872)
- Genesee Valley Railroad
- New York and Erie Railroad (1832 – 1861)
- Buffalo and Southwestern Railroad (1877 – 1880)
- Buffalo and Jamestown Railroad (1872 – 1877)
- Buffalo, New York and Erie Railroad (1857 – 1863)
- Buffalo and New York City Railroad (1851 – 1857)
- Attica and Hornellsville (1845 – 1851)
- Buffalo, Corning and New York Railroad
- Buffalo and Cohocton Valley Railroad
- Rochester and Genesee Valley Railroad (1853 – 1858)
- Buffalo and New York City Railroad (1851 – 1857)
- Avon, Geneseo and Mt. Morris Railroad (1860 – 1872)
- Erie Railway (1861 – 1878)
- Buffalo, Bradford and Pittsburgh Railroad (1895 – 1866)
- Buffalo and Pittsburgh Railroad (1852 – 1859)
- Buffalo and Bradford Railroad (1856 – 1859)