Thomson et al. have introduced the Spectral and Polarisation in Cutouts of Extragalactic sources from the Rapid ASKAP Continuum Survey (SPICE-RACS). In their first data release, they image 30 RACS-low fields in Stokes I, Q, U at 25 arcsecond angular resolution, across 744 to 1032 MHz with 1 MHz spectral resolution to produce a detailed rotation measure (RM) grid. The images are corrected for ionospheric Faraday rotation, primary beam attenuation, and on- and off-axis leakage. The resulting catalogue contains 5818 RM measurements over an area of ∼1300 square degrees: this areal density of ~4 RMs per square degree is an increase of ∼4 times over the previous state-of-the-art. This catalogue has broad applications for studying astrophysical magnetic fields; notably revealing remarkable structure in the Galactic RM sky. The image above shows the RM grid over the area selected for the first data release: a field at intermediate declinations allowing for comparison with previous large-area surveys. Much finer detail can be seen than in previous RM grid determinations.