Originally part of the New York, Oswego and Midland Railroad, Lehigh Valley's Auburn Branch started in Sayre, PA, at the heart of the LV, and extended northward into New York state, and ultimately to its namesake town, Auburn. The line was abandoned in segments -- a majority of the line was deemed unnecessary as a result of the Conrail merger, and most of the tracks were taken up by 1978. The last segment (Locke-Freeville-Dryden-North Harford) was abandoned shortly after April 1, 1978.
Not all is lost, though. Today, a small portion of the line is in tact south of Dryden and operated by the Owego & Hartford. Numerous artifacts remain of this branch line, such as old wooden bridges, a lone switch stand, an abandoned telegraph pole, etc. A derelict roundhouse also stands in Auburn.
More information and additional pictures can be found on Joshua's website.