The main object of this study was to model gravity data in the Big Bend area in order to determine the underlying crustal structure and its possible relation to the Rio Grande rift. Existing data, along with some stations measured for this study, were contoured to produce free air and Bouguer anomaly maps. These maps were compared to those that exist for the region of the rift. In addition, a profile was taken perpendicular to structural trends in the Big Bend area for comparison to profiles modeled across the rift. The same process was used to model this profile as in the studies of the rift to which the profile was compared. A positive Bouguer gravity ridge was found in the region that is similar to that found along the Rio Grande rift by other workers. Since gravity models are not unique solutions, it was necessary to compare other features of the two areas to determine if they were genetically linked. An examination of the structure, geologic history, mineralization, and geophysical characteristics of the two regions revealed certain similarities but many differences. Although the early history of the Big Bend area is similar to that of the Rio Grande rift, the Quaternary history appears to be unrelated.