New Mexico is split between two RECs — Long Beach and St. Louis — and that split is the most informative thing on this page, because it says out loud what the credential system assumes: the file follows the water the service was earned on, not the address on it. In state, Elephant Butte Reservoir is on the Rio Grande and Navajo Lake on the San Juan, two systems that reach the Gulf of Mexico and the Colorado respectively and neither of which is the Mississippi, so 33 CFR 83.03(n) Western Rivers does not touch them. No Part 80 line is drawn in New Mexico either, leaving plain Inland Rules under 83.03(q) on whatever here is navigable water of the United States — a threshold question in its own right on a reservoir, and one for the cognizant Officer in Charge, Marine Inspection rather than for a guide service's own reading.
33 CFR Part 80 draws no demarcation line in New Mexico. Its 106 sections cover the Atlantic, Gulf and Pacific coasts, Puerto Rico and the Virgin Islands, the Pacific islands and Alaska; a state with no coast has no section, which is itself the answer.
This decides which rulebook you steer by, not where your credential may operate: the route limit is the 46 CFR Part 7 Boundary Line, and the two lines are not drawn in the same place. How the two lines differ · International Rules · Inland Rules
33 CFR Part 80 and the Part 83 definitions above read from eCFR on 12 Aug 2026. Any specific water is a determination for the cognizant Coast Guard Officer in Charge, Marine Inspection.