These data are in three tables each reporting estimated iron mineralization within stream reaches from three arctic rivers in northwestern Alaska on select days between July-August, 1985-2022. The relative magnitude of iron mineralization was measured using a remotely sensed iron index calculated from available Level 2, Collection 2, Tier 1 Landsat Surface Reflectance products derived by the USGS and accessed within Google Earth Engine (https://earthengine.google.com).