Few studies have ventured to understand how supercell thunderstorms behave while interacting with complex terrain, though it poses a significant short-term forecasting problem. The few that have investigated this relationship tended to use small sample sizes, limited idealized simulations, or only focused on convection initiated by the terrain. This study aims to fill that gap by analyzing a large observed dataset of supercells interacting with the Appalachian Mountains. A total of 62 isolated supercells observed within the central and southern Appalachians between 2008 and 2019 were analyzed in this study. Each supercell was categorized based on the extent of their interaction with the terrain (either crossing or non-crossing); the majority (37) were classified as non-crossing, while a smaller minority (25) were classified as crossing. Analysis of storm tracks suggest that the extent of terrain effects on supercell maintenance are sensitive to the local topography. To better understand how supercells respond to variations in terrain, each supercell was tracked over its lifetime using GR2 software. Additionally, GIS was used to obtain additional information about the elevation, slope, angle of approach, and aspect. A variety of radar characteristics were collected for each of these storms, including reflectivity, velocity, maximum expected hail size (MEHS), echo tops, and mesocyclone intensity, depth and diameter. The mesocyclone parameters (depth, intensity and diameter) are the most different among crossing and non-crossing supercells. Crossing supercells typically have deeper, stronger, and wider mesocyclones. Based on the results, a list of radar-based thresholds were created to be used in operational settings.