Mangrove Cuckoo is widespread, ranging from southern Florida and northern Mexico south through the West Indies and Central America to the northern tip of South America.
This species is a rare, presumably nonbreeding, visitor to the northern and western coast of the Gulf of Mexico in the United States. Thirteen accepted records occur from the coast of Texas (Mark Lockwood, Texas Bird Records Committee, personal communication), whereas Louisiana, Alabama, and the Panhandle coast of Florida have only single records (Alabama Bird Records Committee 2010, Dittmann and Cardiff 2010, Graves et al. 1982). Texas records are most common from April to August (n = 10); the three remaining records are from December and January. Records from Louisiana, Alabama, and the Panhandle coast of Florida are from December, September, and November, respectively. Differences in the frequency and season of records may reflect differences in the origin of wandering individuals; birds arriving in Texas may come from the Gulf Coast of Mexico and birds along the northern Gulf Coast of the United States may derive from populations in Florida. Graves et al. (1981) suggested that the individual from the Florida Panhandle coast was closer in appearance to C. m. continentalis, which generally refers to birds of the east coast of Mexico and Central America, than C. m. maynardi, believed to be the form found in southern Florida and the Bahamas. However, accurate determination of an individual's population of origin based on plumage color is not possible (Lloyd 2016).
Putative breeding populations occur in Florida from approximately the Tampa Bay region (28° N) south along the Gulf coast to the Florida Keys and Dry Tortugas and then along the coast of the Atlantic Ocean to approximately Miami; scattered sight records from all seasons exist north to roughly 28° N (Stevenson and Anderson 1994).
In Mexico, Mangrove Cuckoos occur inland as far north as Sonora and Tamaulipas and along both coasts as far north on the Pacific side as perhaps Sinaloa (two specimens from 2005 and 2007, respectively: UWBM-81138 and UWBM-84001) and Nayarit, where the species has been recorded breeding on Madre and Magdalena Islands (Grant and McT. Cowan 1964), and as far north on the Caribbean side as Tamaulipas. This species is then found south along both coasts to the borders of Guatemala and Belize.
Although once believed to be largely restricted to coastal lowlands, especially mangroves, there are numerous inland records throughout Mexico, including one from >1,000 m elevation in interior Guerrero (Friedmann et al. 1950). Short (1974) recorded two nonbreeding individuals in the vicinity of Alamos, Sonora during July 1971. In Tamaulipas, Sutton et al. (1950) observed this species "repeatedly" along the Río Sabinas during May 1947 and collected 2 gravid females. Further north on Mesa de Llera, Sutton et al. (1950) collected another gravid female in June of the same year. Eaton and Edwards (1947) collected a male in this same area in June 1946. These inland records from Tamaulipas are notable in that they provide evidence of breeding in short, dry forests (Eaton and Edwards  describe the site of their observation as consisting mostly of short [c.a. 3 m], open mesquite [Prosopis sp.]) distant from the coastal lowlands and at a relatively high elevation (ca. 400 m). The records of Sutton et al. (1950) and Eaton and Edwards (1947) are also the northernmost records of Mangrove Cuckoo in Tamaulipas.
Inland records also exist for Jalisco, where Selander and Giller (1959) reported a lone individual from June 1958 in riparian vegetation in the Barranca de Oblatos, at approximately 900 m elevation and more than 200 km inland from the Pacific Ocean. Winker et al. (1999) reported on a specimen collected in March 1984 well inland (ca. 65 km) of the coast of Tabasco state. Notable inland specimen records include an individual north of Matias Romero in Oaxaca state collected in November 1947 (WFZN-14972) and an individual collected in June 1959 northwest of Tuxtla Gutiérrez, Chiapas state (CUMV-28715). Given the range of known locations for Mangrove Cuckoo in Mexico, it probably can be expected in all physiographic regions excepting the Basin and Range province, the Central Plateau, the Transverse Volcanic Range, Baja California, the Sonoran Desert, and the northern reaches of the Gulf and Pacific Coastal plains.
The distribution of Mangrove Cuckoo in Guatemala and Belize is unclear. Land (1970) was uncertain of their status in Guatemala, although Dickerman (2006) reported them as regular around La Avellana on the Pacific coast. Jones (2003) considered Mangrove Cuckoo a very uncommon resident limited to the coastal plain of Belize, and suggested that habitat loss may have shrunk a once broader distribution within the country.
Mangrove Cuckoo is apparently widespread in El Salvador based on the distribution of specimen records. They occur in a variety of forest types and are not limited to coastal lowlands (Komar 1998). Komar (1998) indicated that both breeding and nonbreeding populations occur in El Salvador.
Distribution in Honduras is relatively unknown; Monroe (1968) suggested that they were probably resident along both Pacific and Caribbean coasts, although any firm conclusions are precluded by the dearth of specimens and definite breeding records. Sight records reported on eBird occur on both coasts and inland. Monroe (1968) considered them a breeding resident on the Bay Islands, and Bond (1936) described them as "fairly common" on Utilla. They are a fairly common migrant on the Swan Islands, with little evidence of breeding (Monroe 1968, Paynter 1956).
An uncommon, permanent resident of mangrove, thorn forest, and scrub on both coasts of Nicaragua (Martínez-Sánchez and Will 2010). Specimens and sight records are scarce from the Caribbean coast, although Peters (1929) found them common and obtained numerous specimens during December 1927 from the Corn Islands.
In Costa Rica, Mangrove Cuckooo is considered an uncommon to "locally fairly common" nonbreeding visitor from December to June (Stiles and Skutch 1989). Most common along the northern Pacific slope; rare further south and along the Caribbean coast (Stiles and Skutch 1989). Apparently rare on the central plateau; Orians and Paulson (1969) reported two sight records from north of Heredia in April and May 1967. Specimens and sight records concentrated along the Pacific coast, with fewer records along the central Plateau, and a handful of records along the Caribbean coast. Almost all sight records in eBird between November and May. Stiles and Skutch (1989) reported no Costa Rican breeding records, but speculated that breeding possibly occurred in lowland Guancaste.
Ridgley and Gwynne (1989) considered the status of Mangrove Cuckoo in Panama "uncertain", with no definite breeding records (although they note the collection of a female in "breeding condition" by Wetmore, presumably USNM 448720). Most specimens and sight records are from the Pacific slope, and almost all date from December through March. A handful of sight records submitted to eBird exist along the Caribbean coast near Colon and inland in the region between Panama City and Colon. Olson (1993) reported on two specimens collected in March 1988 from mangroves in Bocas del Toro, neither in breeding condition and both believed to be wintering migrants. Neither Willis and Eisenmann (1979) nor Robinson (1999) reported Mangrove Cuckoo from Barro Colorado Island. No records exist for the isthmus east of Panama City to the border of Colombia.
The South American distribution of Mangrove Cuckoo appears spotty and is poorly known. On the Colombian islands of San Andres and Providencia, this species is a likely breeder on Providencia (Tye and Tye 1991). It’s status on San Andres is unclear; at least 9 specimens have been collected on the island and Bond (1950a) reported it as "rather rare", whereas 3 subsequent surveys failed to detect it (Paulson et al. 1969, Russell et al. 1979, Tye and Tye 1991). June and Mees (1961) collected two specimens on Trinidad and Tobago: one on Monos Island (October 1953) and one in Caroni Swamp on the island of Trinidad (December 1953). ffrench (1966) reported that Mangrove Cuckoo nest in Caroni Swamp. Hayes and White (2000) reported 5 recent sight records from Tobago, including an individual photographed in July 1994. Mangrove Cuckoo is considered an "irregular" or "casual" nonbreeding visitor to Aruba, Bonaire, and Curacao, although records exist from October – May (Prins et al. 2009, Voous 1985).
On the Colombian mainland, the species is known primarily from "Bogota" trade skins of unknown provenance. Strewe and Navarro (2004) reported a sight record of two individuals from November 2002 in Red Mangrove (Rhizophora mangle) along the Caribbean coast east of Barranquilla in Isla de Salamanca National Park. In Venezuela, Mangrove Cuckoo is known only from several specimens and sight records. At least two specimens come from the Delta Amacuro, including one from near Capure (de Schauensee and Phelps 1978), and another specimen collected on 14 February 1989 at "Isla Punta Brava" in Parque Nacional Morrocoy (UMMZ 627), along the northern coast of Venezuela. Additional sight records exist for these areas and for Islas las Roques, west of Bonaire in the Caribbean Sea (Hilty 2003). Specimens exist from throughout the coastal mangrove belt of Guyana, Suriname, French Guiana, and Brazil (Meyer de Schauensee 1966, Lees et al. 2014). Breeding status throughout these countries is unknown, although Haverschmidt (1965) suspected Mangrove Cuckoo as a regular breeder in mangroves of Suriname.
Mangrove Cuckoo is a year round resident on most of the islands of the West Indies (Raffaele et al. 1998), with the exception of Barbados (Bond 1928) and perhaps several other islands. Substantial uncertainty exists regarding the present day distribution of Mangrove Cuckoo in the northern Lesser Antilles. Ricklefs and Bermingham (2004) suggested that Mangrove Cuckoo was absent from Antigua, Barbuda, St. Eustatius, and Saba, although the species is almost certainly present, if perhaps uncommon, on Antigua and Barbuda. Specimen records and published sight records exist from both Antigua and Barbuda, including the type specimen for the putative subspecies rileyi (Bond 1950b, 1979; Ridgway 1916, Terborgh et al. 1978). Mangrove Cuckoo is probably absent from St. Eustatius and Saba: it was reported neither in the checklist compiled by Voous and Koelers (1967) nor in Terborgh et al. (1978), and no specimen records or other published sight records exist for either island. Raffaele et al. (1998) considered Mangrove Cuckoo absent from St. Eustatius and a vagrant on Saba. Mangrove Cuckoo has been reported absent from St. Kitts, Nevis, St. Barthelemy, and Anguilla (Bond 1979, Steadman et al. 1997, Terborgh et al. 1978), although at least one specimen has been collected on Anguilla (USNM 557692), and Raffaele et al. (1998) list Mangrove Cuckoo as “common” on all of these islands. The species has been collected and observed with some regularity on St. Martin (Bond 1971, 1979; Voous and Koelers 1967), suggesting that Mangrove Cuckoo is probably at least a casual visitor to all of the islands between Antigua and Barbuda and the Virgin Islands. Mangrove Cuckoo is fairly common throughout the Virgin Islands (Askins and Ewert 1991, Cory 1890, Mayer and Chipley 1992, McGowan et al. 2007, Robertson 1962, Wauer and Wunderle 1992).
Common in a variety of habitats in Puerto Rico (Acevedo and Aide 2008, Barnés 1946, Struthers 1923, Terborgh and Faaborg 1973, Wetmore 1916, 1917). A "fairly common" permanent resident throughout Hispaniola and the larger nearshore islands (Latta et al. 2010). Relatively little data available from Jamaica, but apparently common, at least in coastal areas (Field 1894, Scott 1892). In a survey of ten different habitats on Jamaica, Wunderle et al. (1992) reported Mangrove Cuckoo only from mangrove forest. Present and probably a breeding resident on all of the Cayman Islands, with specimen records dating to the earliest collecting efforts (Cory 1886). On Little Cayman, the species was common in closed woodland although surprisingly absent from mangrove forest (Diamond 1980). "Very rare" (Bond 1950b) to uncommon (Raffaele et al. 1998) to locally common in the east of Cuba (e.g., Danforth 1928, Isada et al. 2012, Schwartz and Klinikowski 1963) and especially along mangrove-covered cays, which may be the only locales where nesting regularly occurs (Garrido 1985). A notably inland and western range extension was provided by an individual detected during point-count surveys conducted in June 2000 in the Sierra del Infierno in far western Cuba (Wiley et al. 2002).
A breeding resident of every island group in the Bahamas and Turks and Caicos (Bond 1950b, Vaurie 1953).