Coarse-grained skeletal grainstones and cement-rich packstones of southwestern New Mexico show that intergranular compaction was a major process of porosity destruction. They have lost about 38 percent of their intergranular porosity by intergranular compaction, the remainder having been lost by cementation. Regionally, compaction intensity is greatest in the north. Intergranular pressure solution was the main process affecting intense intergranular compaction and was the reason for compaction intensity being greatest in the north. Bryozoan deformation and grain rearrangement were also important contributors. Of the factors that potentially controlled compaction intensity, chemistry of paleogroundwaters and overburden were probably the most important, whereas bryozoan content, terrigenous clay content, and depositional textures may have been of secondary importance, and tectonic stress was probably of no importance. A major control on intergranular pressure-solution intensity was the degree of saturation with respect to calcite in pre-Pennsylvanian groundwater systems. Groundwaters near and in the recharge regions in the north were undersaturated with respect to calcite. This promoted greater chemical compaction in the north even under low to moderate overburden.--Modified journal abstract.