In January 1930, the U.S. state of New York implemented a major renumbering of its state highways. Many previously existing numbered routes were renumbered or realigned. At the same time, many state highways that were previously unnumbered received designations. Most of the highways with numbers in the 100s to 300s were assigned at this time. Route numbers were assigned in clusters based on their general location. Because some of these route numbers are no longer in use, the pattern of clusters is not fully apparent today.
Pre-renumbering routes
The table below lists the routes in existence just prior to the 1930 renumbering and the effects of the renumbering on these routes. ==Post-renumbering routes==
Post-renumbering routes
The table below lists the routes in existence immediately following the renumbering, including those established as part of the renumbering. An asterisk (*) in the "Pre-1930 designations" column indicates a segment of highway that was previously unnumbered. If the cell in the "Pre-1930 designations" column is empty, then the entirety of the highway was previously unnumbered. 1–99 100–199 200–299 300–399 400 and up ==Notes==