A numerical study on heat distribution and thermal mixing during steady laminar natural convective flow within fluid-saturated porous square cavities has been carried out based on Bejan's heatlines. Three different cases have been considered: (1) uniformly heated bottom wall, (2) discrete heat sources on walls, and (3) uniformly heated left and bottom walls. Studies illustrate that enhanced thermal mixing occurs at higher Da. It is also found that distributed heating enhances heat distribution and thermal mixing compared to uniform heating case. Overall, heatline approach has been found to be a very useful numerical tool to analyze heating strategies in porous media.