We present an assessment of the tropical peatlands in the upper-Ucayali Valley in central Peru—an Amazonian region that has been largely ignored in ecological and wetlands research. We focused on groundtruthing and identifying the strongest landscape-level predictors of peat depth. The 2015 product from the Peruvian Ministry of the Environment (MINAM) appears to be a sufficient proxy, primarily due to its inclusion of the aguajal category, identified as bosque inundable de palmeras (Bi-pal) or palm swamp, which are typically associated with Amazonian peatlands. Aberrations in the MINAM product are also present in attempted updates addressing aguajales, wetlands, and conservation threats, regardless of the varied geographic methodologies employed by previous studies. Our analysis of the CIFOR Global Wetlands Map lends credence to these methodologies, although our results are inconsistent with the depth predictions contained within the product. The predictive strength of factors contained with the MIANM classification is explored, most notably contact segments indicative of transitions from high-terrace terra firma forests (bosque de terraza alta) directly to low-lying inundated and wetland zones. The potential of factors related to elevation (slope, rise, steepness) is likewise questioned based on their performance in multiple linear regression analyses. Future studies are needed to enhance our understanding of the hydrogeologic settings and associated geochemical attributes of palm swamps and peatlands in The Amazon.