This paper examines Mexican regional patterns. Different regional definitions are utilized to examine in-/out-migration patterns in 4 different periods: 1) 1979-1980, 2) 1975-1979, 3) prior to 1975, and 4) lifetime. 5 regional definitions previously used to delineate state level Mexican regions were compared to new regions by a maximum likelihood clustering technique. Previously defined regions do not compare with the empirically delineated regions developed by the cluster analysis. A cluster analysis of in-/out-migration patterns suggests the following: 1) distinct in-/out-migration patterns for both short- and long-term migration patterns, 2) a central region consisting of Mexico and the Federal District having its own distinct regional characteristics for both in-/out-migration patterns, particularly intraregional migration among those 2 states exceeds any other interregional migration patterns, and 3) the unique role played by Jalisco in mediating long-term inflows prior to 1975, and since 1975, out-migration from the same state. Previous research rarely identified the Central region consisting of Mexico and the Federal District. Using net migration for interregional migration analysis may possibly be misleading since immigration and out-migration phenomena show distinct patterns of geographic mobility at the state level, and such regional differences are consistent for the 4 migration periods. A careful analysis accounting for both distinct migration patterns in the Central region and different patterns in in-/out-migration are necessary to obtain an understanding of regional migration patterns in Mexico.