This study investigates the hidden carbon reservoirs in forested wetlands, which are not included in current maps and are referred to as 'cryptic carbon'. The researchers measured and mapped soil organic carbon (SOC) stocks across the Hoh River Watershed (HRW) in the Pacific Northwest of the U.S., a region with 68,145 ha of land. They found that total SOC at 30 cm depth was 5.0 TgC, which is between estimates from global SOC maps (3.9 TgC) and SoilGrids (7.8 TgC). For wetland SOC, their 1 m stock estimates were significantly higher (Mean: 259 Mg ha\(^{-1}\); Total: 1.7 TgC) compared to current wetland-specific SOC maps (Mean: 184 Mg ha\(^{-1}\); Total: 0.3 TgC). The study identified 1.5 TgC of unmapped or cryptic carbon, which, when added to current estimates, increases the estimated wetland SOC stock to 1.8 TgC, a 482% increase. This highlights the significant amount of SOC that is not mapped and is contained in unprotected and vulnerable wetlands. The research emphasizes the importance of conserving these carbon-rich ecosystems to meet the goals of balancing carbon sources and sinks for the Paris Climate Agreement. The study also discusses the challenges in mapping wetland SOC due to poor spatial representation and the need for more comprehensive SOC mapping that accounts for high SOC in forested wetlands. The results show that forested wetlands contain a substantial amount of SOC, with the majority of it stored in the top 1 m of the soil profile. The study developed a statistical model to predict SOC stocks based on the Wetland Intrinsic Potential (WIP) probability, which identified a continuous gradient of SOC stocks from uplands to wetlands. The model predicted a mean 1 m SOC stock of 127 ± 26.0 MgC ha\(^{-1}\) and a mean 30 cm SOC stock of 72.9 ± 12.5 MgC ha\(^{-1}\). The study concludes that the identification of cryptic carbon is crucial for improving wetland carbon monitoring systems and for better conservation of these valuable carbon sinks.This study investigates the hidden carbon reservoirs in forested wetlands, which are not included in current maps and are referred to as 'cryptic carbon'. The researchers measured and mapped soil organic carbon (SOC) stocks across the Hoh River Watershed (HRW) in the Pacific Northwest of the U.S., a region with 68,145 ha of land. They found that total SOC at 30 cm depth was 5.0 TgC, which is between estimates from global SOC maps (3.9 TgC) and SoilGrids (7.8 TgC). For wetland SOC, their 1 m stock estimates were significantly higher (Mean: 259 Mg ha\(^{-1}\); Total: 1.7 TgC) compared to current wetland-specific SOC maps (Mean: 184 Mg ha\(^{-1}\); Total: 0.3 TgC). The study identified 1.5 TgC of unmapped or cryptic carbon, which, when added to current estimates, increases the estimated wetland SOC stock to 1.8 TgC, a 482% increase. This highlights the significant amount of SOC that is not mapped and is contained in unprotected and vulnerable wetlands. The research emphasizes the importance of conserving these carbon-rich ecosystems to meet the goals of balancing carbon sources and sinks for the Paris Climate Agreement. The study also discusses the challenges in mapping wetland SOC due to poor spatial representation and the need for more comprehensive SOC mapping that accounts for high SOC in forested wetlands. The results show that forested wetlands contain a substantial amount of SOC, with the majority of it stored in the top 1 m of the soil profile. The study developed a statistical model to predict SOC stocks based on the Wetland Intrinsic Potential (WIP) probability, which identified a continuous gradient of SOC stocks from uplands to wetlands. The model predicted a mean 1 m SOC stock of 127 ± 26.0 MgC ha\(^{-1}\) and a mean 30 cm SOC stock of 72.9 ± 12.5 MgC ha\(^{-1}\). The study concludes that the identification of cryptic carbon is crucial for improving wetland carbon monitoring systems and for better conservation of these valuable carbon sinks.