Lamphun Highway District is a regional agency of the Department of Highways under the supervision of Highway Bureau No. 1. Its main responsibilities are to plan and carry out routine maintenance, special maintenance, periodic maintenance, rehabilitation works, and highway preservation in order to ensure that highways remain in normal operating condition, convenient, and safe.

Lamphun Highway District has authority and responsibility over highways within Lamphun Province, including Mueang Lamphun District, Pa Sang District, Ban Hong District, Mae Tha District, Li District, Thung Hua Chang District, Ban Thi District, and Wiang Nong Long District, with the following duties and responsibilities:

1. Planning highway maintenance works, highway safety operations, and small-scale construction projects.
2. Surveying, inspecting, and preparing plans and data related to highway construction material sources and preliminary road conditions.
3. Carrying out highway maintenance works, highway safety operations, and small-scale construction projects.
4. Performing preventive maintenance, adjustments, and minor repairs of machinery, vehicles, tools, and equipment used for construction and highway maintenance under responsibility.
5. Implementing public participation activities in areas with highway construction, rehabilitation, and maintenance projects.
6. Inspecting, supervising, and enforcing highway-related laws as assigned.
7. Processing permits in accordance with highway laws as delegated.
8. Operating and managing mobile vehicle weight control stations.
9. Supporting and cooperating with provincial authorities and other agencies.
10. Cooperating with or supporting the operations of other relevant agencies as assigned.