This report characterizes the amplitude and wavelength content of the current track geometry environment of the United States railroad system and examines the combination of geometric parameters for different operational conditions. The analyzed track geometry dataset consists of over 49,000 miles of track in the United States, measured between 2012 and 2019. The types of characterization used in this study include statistical, frequency-based, and clustering analyses. The single-variable and bivariate statistical tables in this report can be used to estimate the likelihood of encountering alignment and surface irregularities or combinations of the two of any given magnitude in various FRA track classes. The typical irregularity shapes identified by means of clustering can be used in further track geometry studies to determine the shapes most detrimental to the vehicle-track system’s safety. A combination of the statistical tables and clustering analysis can be used to construct artificial combined track geometries for further study and as an input to vehicle-track interaction simulation models.