  We obtain a quantitative star formation history (SFH) of a shell-like
structure ('shell') located in the northeastern part of the Small Magellanic
Cloud (SMC). We use the Survey of the MAgellanic Stellar History (SMASH) to
derive colour-magnitude diagrams (CMDs), reaching below the oldest
main-sequence turnoff, from which we compute the SFHs with CMD fitting
techniques. We present, for the first time, a novel technique that uses red
clump (RC) stars from the CMDs to assess and account for the SMC's
line-of-sight depth effect present during the SFH derivation. We find that
accounting for this effect recovers a more accurate SFH. We quantify a 7 kpc
line-of-sight depth present in the CMDs, in good agreement with depth estimates
from RC stars in the northeastern SMC. By isolating the stellar content of the
northeastern shell and incorporating the line-of-sight depth into our
calculations, we obtain an unprecedentedly detailed SFH. We find that the
northeastern shell is primarily composed of stars younger than 500 Myrs, with
significant star formation enhancements around 250 Myr and 450 Myr. These young
stars are the main contributors to the shell's structure. We show synchronicity
between the northeastern shell's SFH with the Large Magellanic Cloud's (LMC)
northern arm, which we attribute to the interaction history of the SMC with the
LMC and the Milky Way (MW) over the past 500 Myr. Our results highlight the
complex interplay of ram pressure stripping and the influence of the MW's
circumgalactic medium in shaping the SMC's northeastern shell.
