Marshfield Municipal Airport (IATA: MFI, ICAO: KMFI, FAA LID: MFI) is a city owned public use airport located one nautical mile (2 km) south of the central business district of Marshfield, a city in Wood County, Wisconsin, United States. It is included in the Federal Aviation Administration (FAA) National Plan of Integrated Airport Systems for 2021–2025, in which it is categorized as a local general aviation facility.

Marshfield Municipal Airport covers an area of 552 acres (223 ha) at an elevation of 1,278 feet (390 m) above mean sea level. It has two asphalt paved runways: the primary runway 16/34 is 5,002 by 100 feet (1,525 x 30 m) with approved GPS and NDB approaches; the crosswind runway 5/23 is 3,597 by 100 feet (1,096 x 30 m) also with approved GPS and NDB approaches.

The non-directional beacon navigational aid associated with the airport is the Marshfield NDB (MFI), 391 kHz, which is located on the field.

For the 12-month period ending August 2, 2023, the airport had 23,050 aircraft operations, an average of 63 per day: 88% general aviation, 11% air taxi and less than 1% military. In August 2024, there were 16 aircraft based at this airport: 11 single-engine, 3 multi-engine, 1 jet and 1 helicopter.

• List of airports in Wisconsin

• "Marshfield Municipal (MFI)" (PDF). at Wisconsin DOT airport directory
• FAA Terminal Procedures for MFI, effective October 3, 2024
• Resources for this airport:
  • FAA airport information for MFI
  • AirNav airport information for KMFI
  • ASN accident history for MFI
  • FlightAware airport information and live flight tracker
  • NOAA/NWS weather observations: current, past three days
  • SkyVector aeronautical chart, Terminal Procedures