We present experimental results for microwave intermodulation in a series of superconducting hairpin resonators. We find that geometry plays a dominant role in determining both the losses and intermodulation in these resonators. The experimental data can be reproduced using recent theoretical calculations with a single parameter,JIMD (77 K). We compare the response of the fundamental and the first harmonic modes of these resonators to find that the use of the first harmonic mode gives less intermodulation, but we also find higher losses due to the more extended fields of this mode. ©1997 American Institute of Physics.