The `1dTTG_mc_code` is a Fortran-based Monte Carlo simulation program specifically developed for analyzing one-dimensional Transient Thermal Grating (TTG) experiments. This digital resource provides a powerful computational approach to investigate thermal transport phenomena at the nanoscale, offering an alternative or complementary method to solving the Boltzmann Transport Equation (BTE) directly. Its primary utility lies in simulating the time-dependent thermal response of materials to spatially periodic heating, a common technique in experimental thermal physics. This code's core functionality revolves around a Monte Carlo algorithm, which is well-suited for simulating particle-based transport, such as phonons in solids. By using a Monte Carlo approach, it can capture the stochastic nature of phonon scattering and propagation, providing insights into non-equilibrium thermal processes. Fortran, the programming language used, is renowned for its high performance in numerical computations, especially when handling large arrays and matrices, which is typical in physics simulations. The `1dTTG_mc_code` is particularly valuable for researchers studying the fundamental aspects of heat conduction, including phonon mean free path accumulation functions and effective thermal conductivity in various materials. It can be applied to understand how thermal energy propagates and dissipates in confined geometries or under transient conditions, which are critical for the development of advanced thermal management solutions. The code's output can be compared with experimental data from transient thermal grating setups, aiding in the validation of theoretical models and the characterization of material properties. To utilize this resource, users will require a Fortran compiler. While specific dependencies are not explicitly detailed in public search results, typical Fortran scientific codes often rely on standard libraries for mathematical operations. The GitHub repository serves as the primary source for the code and any specific instructions for compilation and execution. Its development by Samuel Huberman, a researcher in thermal transport, suggests its foundation in rigorous scientific principles and its utility for academic and industrial research in thermal engineering and materials science.