The East Broad Top Railroad (reporting mark EBT) is a 3 ft (914 mm) narrow gauge historic and heritage railroad headquartered in Rockhill Furnace, Pennsylvania. Operating from 1871 to 1956, it is one of the United States' oldest and best-preserved narrow-gauge railroads, and was designated a National Historic Landmark in 1964. The railroad is now preserved for use as a tourist attraction until operations ceased in 2011. After a nine-year closure, in February 2020 it was announced that the railroad had been purchased by a non-profit foundation and regular train service resumed in the summer of 2021.

The EBT is unusual in that it is a complete, original railroad rather than a collection of pieces from various locations, as most tourist railroads are. All six of the 3 ft narrow-gauge steam locomotives that operated on the railroad in its last years as a coal hauler are still on site, and some were used for the excursion trains. Other original equipment includes a 4 ft 8+1⁄2 in (1,435 mm) standard gauge switcher steam locomotive (non-operational), operating track-gang cars, the M-3 motorcar (built from scratch by the EBT with an engine and transmission from an automobile), and the M-1, a motorcar (doodlebug) based on scaled-down J. G. Brill and Company plans built by the EBT in 1927. The majority of rolling stock that operated on the railroad in its later coal-hauling years remains on the property in varying condition, including over a dozen flatcars, several boxcars and well over 150 hoppers. Tourist trains used original EBT passenger equipment, as well as converted EBT freight cars. The original railroad maintenance shops have a pair of Babcock & Wilcox boilers, a 19th-century stationary steam engine, and an overhead line shaft system (steel shafts, wood and iron pulleys and leather and canvas belts) that powers antique machine tools, sheet-forming machines, foundry equipment, blacksmithing tools and woodworking machines. Almost 33 miles (53 km) of the railroad's original line is still in place, though only 5 miles (8.0 km) are usable. In recent years, disused trackage from Rockhill Furnace southward and Robertsdale southward have been cleared and gauged for use with speeders and handcars (track-gang cars).

The EBT was designated a National Historic Landmark in 1964 and added to the National Register of Historic Places in 1966. The railroad was added in 1996 to the National Trust for Historic Preservation's list of America's Most Endangered Places.

The East Broad Top Railroad and Coal Company was chartered in 1856. Due to financial constraints and the American Civil War, the railroad was not built by its original charterers, but a new group of investors began to acquire right-of-way in 1867 and was able to construct the railroad as a 3 ft (914 mm) narrow gauge line in 1872–1874. Service began from Mount Union, Pennsylvania to Orbisonia, Pennsylvania in August, 1873, and to Robertsdale in November, 1874. The line later was extended to Woodvale and Alvan, with several short branches. At its height, it had over 60 mi (97 km) of track and approximately 33 mi (53 km) of main line.

The primary purpose of the railroad was to haul semi-bituminous coal from the mines on the east side of the remote Broad Top Mountain plateau. In its first few decades, the railroad hauled most of the coal to Rockhill to be coked and used in iron production in the furnaces of the Rockhill Iron and Coal Company, its sister company. It then hauled the pig iron from the furnace. Shortly after the turn of the 20th century, the railroad transitioned to haul most of the coal to Mount Union to be processed and transferred to the Pennsylvania Railroad. The railroad also carried substantial amounts of ganister (orthoquartzite rock, used for furnace lining), lumber and passengers with some agricultural goods, concrete, road tar and general freight.

As the iron industry in the region faded in the early 1900s, the railroad came to subsist on coal traffic for about 90% of its revenue. Large plants for the manufacture of silica brick were developed at Mount Union around the turn of the 20th century, and these became major customers for coal and also for ganister rock, which was quarried at multiple points along the railroad. At Mount Union the yard consisted of dual gauge trackage. EBT had an enginehouse for two standard gauge locomotives which handled switching between the standard and narrow gauge sides of the coal cleaning plant.

The EBT maintained an office in Philadelphia, PA. An 1893 timetable lists their executive offices at 320 Walnut St., then the main commercial area of the city. The city's business center migrated west and by 1939 the EBT's office was at 1421 Chestnut St. EBT was generally profitable from the 1880s through the 1940s and was able to modernize its infrastructure far more than other narrow gauge railroads. The railroad's roundhouse, one of the oldest railroad roundhouses in the US still in operation, was built in 1882. A coal cleaning plant and a full maintenance shops complex were also built, bridges were upgraded from iron and wood to steel and concrete, wood rolling stock was replaced by steel, and modern high-powered steam locomotives were bought from the Baldwin Locomotive Works of Philadelphia. In the post-WWII years most railroads converted to diesel motive power but the EBT considered this switch unnecessary. Steam locomotives had proven longevity and, as EBT was a coal carrier, fuel was abundant and cheap.

In 1929 the EBT formed the East Broad Top Transit Company and operated regional bus service. It acquired the Mount Union Bus Line in 1931. In 1941 this operation was sold to the Huntingdon Bus Company.