The Acajutla debris-avalanche deposit is dated to about 40,000 cal BP. The dating is based on two 14C dates on pieces of wood from the debris-avalanche deposit recovered from a core at the Santa Águeda School Center. The debris-avalanche deposit overlies a 1.2-m-thick paleosol and four ash layers. One of these ash layers is geochemically correlated to the Los Chocoyos ash from Atitlán Caldera, while the others are possibly from eruptions of Coatepeque and Ilopango Calderas. The new data, collected in well reports from the years 1966 to 2019, include deposit thicknesses identified in 25 wells for water monitoring, bathymetric data from nautical charts, GEBCO’s grids, updated topographic data from LIDAR, and a reassessment of the deposit’s lateral limits. This new data will allow us to better constrain the volume of the Acajutla debris-avalanche deposit.