any, machine learning model and covariate set might be optimal for predicting soil classes across 23 different landscapes. 24Our objective was to compare multiple machine learning models and covariate sets for predicting soil 25 taxonomic classes at three geographically distinct areas in the semi-arid western United States of 26 America (southern New Mexico, southwestern Utah, and northeastern Wyoming). All three areas were 27 the focus of digital soil mapping studies. Sampling sites at each study area were selected using 28 conditioned Latin hypercube sampling (cLHS). We compared models that had been used in other DSM 29 studies, including clustering algorithms, discriminant analysis, multinomial logistic regression, neural 30 networks, tree based methods, and support vector machine classifiers. Tested machine learning models 31 were divided into three groups based on model complexity: simple, moderate, and complex. We also 32