This paper presents the fundamental components of the Least Squares Modification of the Stokes integral with Additive corrections (LSMSA) to geoid determination. This method also known as the KTH method is theoretically described, then it is applied to the western part of North Macedonia. In this regard, input data is firstly explained, and then various geoid models are created in the test area. Finally, all geoid models are evaluated against the ground truth to get a final geoid model. Numerical results indicate that despite of limited terrestrial gravity data, a precise geoid model by LSMSA method is computed in the test area.