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 numbered in the 100s to 300s were created at this time, with route numbers assigned in clusters based on their general location. Several of these new routes no longer exist, so the pattern of clusters is no longer fully obeyed today.

The system that had been in place prior to 1930 was established in the 1920s. During this time, New York only numbered a small set of its state highways. Route numbers were from 1–80, with generally north–south routes having even numbers and generally east–west routes having odd numbers. This scheme was abandoned with the advent of the U.S. Highway System in 1927. There was some renumbering done in 1927 to avoid overlapping route numbers.

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

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.

Routes 1–100

Routes 101–200

Routes 201–300

Routes 301–400

Routes 401 and up