From the 1920s to the mid-1980s, International Harvester (IH) serial number plates represent the key to understanding virtually every tractor the company built. However, IH's system was far from simple. It changed over time, varied between factories, and is rife with nuances that many owners overlook. This guide teaches you exactly how to find, read, and decode any IH tractor serial number using the original factory tables.
International Harvester Company (IH) produced farm tractors from 1906 until 1985 (when the agricultural division was sold to Tenneco, forming Case IH). To track production, identify model year, and verify authenticity, IH used serial number plates attached to the tractor’s chassis. Serial number tables (often found in service manuals, parts catalogs, and enthusiast guides) provide the cross-reference between serial number ranges and the corresponding year of manufacture.
This format typically appears as a long string of characters (e.g., 2590009U004452 ):
Common locations across major IH tractor generations include: IH Tractors - identifying model from serial number International Harvester Tractor Serial Number Table-
In 1954, IH updated its lineup with torque amplifiers, live hydraulics, and two-tone white and red paint schemes. Farmall 300 (1954–1956) The successor to the Farmall Super H. Starting Serial Number 1955 1956 Farmall 400 (1954–1956) The successor to the Farmall Super M. Starting Serial Number 1954 1955 1956 IH 06 & 56 Series
This is the most common mistake. IH produced two main lines of tractors:
The following tables provide a chronological overview of serial numbers for International Harvester's major tractor series. From the 1920s to the mid-1980s, International Harvester
| Plant | Serial Number Range | | :--- | :--- | | Farmall Plant | 501–12515 | | Louisville Plant | 500001–501905 |
: Plates are frequently attached to the left-hand side of the transmission housing, right underneath the driver’s seat.
: Located on the right side of the steering gear housing, near the operator's platform. 3. The Number Series (Hundreds and 06/56/66 Series) Look on the left or right side of the transmission housing. This guide teaches you exactly how to find,
This article provides a deep dive into using serial number tables, explains the nuances of IH numbering systems across six decades, and offers a comprehensive reference table for the most popular models.
: Industrial configuration (often painted yellow with heavy-duty front axles).
While you can find hundreds of serial number tables on forums like RedPower Magazine or Yesterday’s Tractors , beware of inaccuracies. Many online tables are user-submitted and contain typos.