In April 1980, nearly synoptic hydrographic observations were obtained in the western Gulf of Mexico by satellite and ship. A meandering surface thermal front which turned northeastward from the Mexican coast near 23 ¿N was prominent in the satellite infrared observations. The front separated a southern anticyclone and a northern cyclone, both of which had horizontal scales of several 100 km and were prominent in the subsuface hydrographic observations. The eastward geostophic volume transport in the confluent leg of the two features was roughly equal to that of the Florida Current. A shallow layer of fresh, cool water from the Texas shelf region extended ~300 km seaward into the cyclone along the northern side of the front. Remnant Subtropical Underwater in the core of the April anticyclone indicates its origin in the eastern Gulf Loop Current.