As part of the US Coral Reef Task Force's National Program to Map, Assess, Inventory, and Monitor US Coral Reef Ecosystems, a comprehensive survey of projects/programs monitoring coral reef ecosystems and related habitats (i.e., seagrass beds and mangroves) in the US Caribbean and Pacific was undertaken. Information was gathered on a total of 296 monitoring and assessment projects conducted since 1990 in the US Caribbean and the Gulf of Mexico. Substantial gaps in monitoring coverage of US coral reef ecosystems were revealed through geographic information system (GIS) analysis of survey metadata. Although southern Florida contains approximately two-thirds of all marine monitoring projects found in the US Caribbean and Gulf of Mexico, we were unable to identify any ongoing projects that monitor coral reefs along Florida's western coast and off of the Florida Middle Grounds. Additionally, Florida is covered by approximately 1 900 km2 of mangroves, yet there were only four ongoing projects that monitor this ecosystem, leaving gaps in coverage in the Lower and Middle Keys and along the eastern and western coasts. The Flower Garden Banks National Marine Sanctuary, located offshore of the Texas/Louisiana border, has an integral long-term monitoring program, but lacks a monitoring project that gathers long-term, quantitative data on reef fish abundance and certain water quality parameters. Numerous coral reef monitoring projects in Puerto Rico are concentrated on the island's southwestern coast surrounding La Parguera, while far fewer monitoring projects are conducted along the northern and southeastern coasts and around Vieques Island. In the US Virgin Islands, the paucity of monitoring projects in large areas of St. Croix and St. Thomas contrasts with monitoring activity in three marine protected areas (MPAs), where 66% of the US Virgin Islands' coral reef monitoring sites were found. Only a series of assessments have been conducted at Navassa, a small, uninhabited island located 55 km west of Haiti and 137 km northeast of Jamaica. In order to better understand changes in coral reef communities and to produce a series of biennial reports on the status of US coral reef ecosystems, the National Oceanic and Atmospheric Administration (NOAA) is developing a national coral reef monitoring network. This network has already begun to fill some of these gaps in monitoring coverage through issuing cooperative grants to states and territories to build long-term monitoring capacity.La Administración Nacional del Océano y la Atmósfera llevó acabo una encuesta de 296 programas / proyectos que han evaluado y mo-nitoreado desde 1990 los arrecifes coralinos y sus hábitats asociados (i.e., las hierbas marinas y los manglares) en las áreas estadounidenses del Caribe y el Golfo de México. Al analizar los resultados usando un sistema de información geográfica, se encontraron varias brechas substanciales en el alcance de estos proyectos debida a la distribución desigual de sitios donde se monitorean los recursos marinos. Hay una densidad alta de proyectos que investigan los arrecifes en los Cayos Altos de Florida y La Parguera, Puerto Rico. Mientras que en otras zonas, como la costa oeste de Florida, los Florida Middle Grounds, las costas norteña y sudeste de Puerto Rico, la Isla Vieques, varias partes de St. Thomas y la Isla Navassa, la es-casez de los estudios científicos domina. Aunque múltiples proyectos mapean las hierbas marinas y los manglares, estos ecosistemas apenas están monitoreados a lo largo del Caribe estadounidense. Para incrementar el al-cance geográfico de estos proyectos, la Administración Nacional del Océano y la Atmósfera ha comenzado a otorgar becas a algunos estados y territorios para que amplíen su capacidad de evaluar la condición de su ambiente costero a largo plazo.