The Moon and Mars have strong regional crustal magnetic fields as shown by the observations of orbiting spacecraft. These crustal magnetic fields indicate that a core dynamo was present in the past, and it is believed that rocks formed from cooling lava retain a memory of the strength and orientation of the magnetic field that existed during their solidification. However, a major hurdle in understanding the crustal magnetic field structure is the low spatial resolution limited by the altitude of the orbiting spacecraft. Rovers are well suited for exploring the detailed structure of the crustal magnetic fields, but they also present a technical challenge due to the necessity that sources of magnetic interference from the rover be removed from the measurements. We designed a compact rover dedicated to measuring the detailed spatial distribution of the surface magnetic field. The rover is equipped with an array of magnetic sensors mounted in a rectangular grid that aims to differentiate the rover components’ own magnetic fields from the ambient magnetic field. Another magnetic sensor is placed on top of an extendable arm to provide additional measurements for verifying the ambient magnetic field inferred from grid-point measurements. The rover consists of four wheels, a Raspberry Pi single-board computer, control circuitry, and a chassis that holds the magnetometers in a rectangular array. In the prototype of the rover, commercial small-scale microelectromechanical systems (MEMS) magnetometers are used for magnetic field measurements. The test results from these design features can provide a useful reference for future lunar or Martian surface missions with rover-based experiments that measure crustal magnetic fields.