Burgos is the largest gas producing basin in Mexico. This analysis discusses the fields in the Burgos and the Sabinas basins that are not part of the Multiple Service Contracts (MSCs). The minor fields in the Sabinas basin form part of Pemex's Burgos business unit and are included in this analysis. The Burgos basin lies in the northeast of Mexico, in the states of Tamaulipas and Nuevo León. It is one of two principal Tertiary sedimentary basins that form the ancestral Gulf of Mexico. The Sabinas basin is located in northern Mexico in the state of Coahuila, close to Burgos. Sabinas is an intracratonic basin located entirely onshore and covers 37,000 square kilometres.