This dataset contains maps (GeoTIFFs) of soil pH of six standard depth layers for the Netherlands at 25 m resolution. The six standard depth layers are from 0-5 cm, 5-15 cm, 15-30 cm, 30-60 cm, 60-100cm and 100-200cm. For each of these depth layers, there is a map of mean predictions, the 5th, 50th (median) and 95th quantile, as well as the 90% prediction interval (PI90 = 95th - 5th quantile) and a categorical map of the accuracy thresholds ("none", A, AA and AAA) based on GlobalSoilMap specifications for Tier 4 products. The accuracy thresholds were derived from the PI90, which is a measure of prediction uncertainty. All maps are based on predictions (mean) and estimations (quantiles) using a Quantile Regression Forest model, which was calibrated using 15338 soil pH measurements from the "Bodemkundig Informatie Systeem" (BIS) and 195 covariates (spatially explicit environmental variables of soil forming factors). ...