The dataset includes stratigraphic information for boreholes of ten cross sections that were hand drilled from 2013-2015 CE in the bayhead region of the Lafourche subdelta, Mississippi Delta, USA. The study area spans ~6000 km2 and the cross sections are located near distributary channels. Data herein describe the location, surface elevation, and depth of each borehole as well as the depth relative to the surface of the mouth-bar to overbank (M-O) boundary and OSL ages for the mouth-bar deposits. We used these data to estimate centennial- to millennial-timescale cumulative subsidence and subsidence rates of a buried stratigraphic horizon, the M-O boundary, as detailed in the associated publication. Subsidence calculation methods are presented in the dataset, and subsidence data obtained from peat-top elevations at a relatively inland site (Paincourtville, LA, USA) are presented for comparison.