State Routes are signed with the circular highway shield.

Major routes are typically assigned one- or two-digit numbers, except where the numbers were chosen to match an adjacent state.

Most numbers from 1 to 50 follow a general geographic pattern assigned in 1927 (details below), but later additions are more haphazard.

The new numbers followed a general geographical pattern from north to south - 1–12 in northern New Jersey, 21-28 roughly radiating from Newark, 29-37 from Trenton, 38-47 from Camden, and 48–50 in southern New Jersey.

As the system grew, some numbers beyond 50 were used, but most new routes received prefixed or suffixed labels.

The two planned toll roads — the Garden State Parkway and New Jersey Turnpike - received only those names; they had been numbered 4 Parkway and 100.

Minimal disruption was caused by the assignment of Interstate Highway numbers in the late 1950s.