The section of NY 205 between I-88 and the northern terminus of the NY 23 overlap is the only section included in the National Highway System. The National Highway System is a system of highways important to the nation's defense, economy, and mobility. The functional classification of NY 205 is Principal Arterial from I-88 to the northern overlap of NY 23, and Minor Arterial for the rest of its length. Functional classification is the process by which roads, streets, and highways are grouped into classes according to the character of service they provide.