Coastal wetlands, including salt marshes, have the potential to sequester vast amounts of carbon and store it over decennial and multi-millennial timescales. Unlike terrestrial ecosystems, salt marshes do not become carbon saturated over time as they subside under their own weight, increasing bulk density and allowing for continued accretion through sedimentation and biomass production. Salt marshes along San Francisco Bay have been recorded to keep pace with sea level rise, suggesting these ecosystems have the potential to function as negative feedback mechanisms in climate change mitigation. Our project began an investigation into the ability of the salt marshes of Humboldt Bay to sequester and store carbon. This was done through determining soil organic carbon (SOC) content and extrapolating sequestration rates from proxy studies. We measured total area, SOC, and potential carbon storage in metric tons of the salt marshes within the jurisdiction of the City of Arcata. We found ~481 acres of salt marsh to currently exists. Through GIS analysis of 1870 maps we determined ~1418 acres of salt marsh at that time, the loss occurring due to diking and land conversion for agricultural purposes. Through calculations using data from our sampling as well as other studies of salt marshes along the west coast, we project that salt marshes within the City of Arcata currently sequester about 396 metric tons (mT) of carbon per year. If the lands which were historically salt marsh were to be restored, around 1169 mT would be sequestered annually. We also measured SOC of an agriculture field which was salt marsh prior to conversion, as well as the amount of subsidence which has occurred due to conversion.