We present a technique to fit the stellar components of the Galaxy by comparing Hess Diagrams ( HDs ) generated from Trilegal models to real data . We apply this technique , which we call mwfitting , to photometric data from the first three years of the Dark Energy Survey ( DES ) . After removing regions containing known resolved stellar systems such as globular clusters , dwarf galaxies , nearby galaxies , the Large Magellanic Cloud and the Sagittarius Stream , our main sample spans a total area of \sim 2,300 deg ^ { 2 } . We further explore a smaller subset ( \sim 1,300 deg ^ { 2 } ) that excludes all regions with known stellar streams and stellar overdensities . Validation tests on synthetic data possessing similar properties to the DES data show that the method is able to recover input parameters with a precision better than 3 % . We fit the DES data with an exponential thick disk model and an oblate double power-law halo model . We find that the best-fit thick disk model has radial and vertical scale heights of 2.67 \pm 0.09 kpc and 925 \pm 40 pc , respectively . The stellar halo is fit with a broken power-law density profile with an oblateness of 0.75 \pm 0.01 , an inner index of 1.82 \pm 0.08 , an outer index of 4.14 \pm 0.05 , and a break at 18.52 \pm 0.27 kpc from the Galactic center . Several previously discovered stellar over-densities are recovered in the residual stellar density map , showing the reliability of mwfitting in determining the Galactic components . Simulations made with the best-fitting parameters are a promising way to predict MW star counts for surveys such as the LSST and Euclid .