The reversal process of thin film micron-scale Co/Cu/NiFe rhombic rings in an in-plane magnetic field is investigated by micromagnetic simulation and magnetoresistance measurements. Simulations show that the impingement of reverse domains leads to the formation of multiple 360° domain walls in the ring during low-field cycling. Two types of reversal process can be identified experimentally which are attributed to the presence or absence of residual 360° domain walls in the ring. The reversal path depends on the field history, which affects the population of walls in the ring.