White-throated Flycatcher is found from Mexico south to western Panama. Within this region, its distributional range is poorly known, and published maps often are incorrect. The estimate of its area of occurrence as 1,500,000 km2 (BirdLife International 2018) includes much territory from where the bird has never been reported and is likely incorrect, as this estimate does not distinguish between breeding grounds and wintering grounds. Distribution maps shown in BirdLife International (2018) and Farnsworth and Lebbin (2004) include much of the Pacific lowlands in northern Central America as part of the wintering range, but there are no published records from that area.
Range in Mexico: In Mexican interior, found from southwestern Chihuahua (Sierra Madre Occidental) through the Central Volcanic Belt to Sierra Madre del Sur (Oaxaca); also found in Sierra Madre Oriental from southern Tamaulipas to Oaxaca, and in Chiapas. Typically breeds in the highlands (1200–3000 m) and winters in marshes from sea level to 1200 m (Howell and Webb 1995). In recent years, has been found at lowland locations throughout Mexico, for example in Tamaulipas (Garza-Torres et al. 2003), and Oaxaca (Peterson et al. 2003).
Range in Central America: Found in highlands of Guatemala, El Salvador, Honduras and northwest Nicaragua, and, south of the Nicaraguan Depression, again locally in the highlands of central Costa Rica and western Panama.
Griscom (1932) was the first to speculate that this species is an altitudinal migrant, because at that time, “all definite breeding records […] are from 2500 to 5000 feet above sea-level [i.e. 762-1524 m]. All lowland tropical records are based on specimens taken at other seasons. There is no evidence as yet of any migration, other than a possible descent to lower levels in the non-breeding season. Recorded from central Mexico to western Panama, definitely known to breed in Veracruz, the highlands of Guatemala, northern Nicaragua and Costa Rica". Howell and Webb (1995) confirmed its status as an altitudinal migrant for Mexico, and although definitive evidence from radio-tracking or band recovery studies is still lacking for Central America, highland records during the breeding season and lowland records from the nonbreeding season suggest that White-throated Flycatcher is an altitudinal migrant throughout the range.
Both Stiles and Skutch (1989) and Ridgely and Gwynne (1989) speculated that lowland records from Costa Rica and from Panama, respectively, potentially were migrants from the northern part of the range. For example, Ridgely and Gwynne (1989) give an elevational range of 1200–1800 m for Panama, but note two specimen records from the lowlands, which they speculate were either wanderers from the highlands or, possibly, migrants from farther north in Middle America. In Honduras, highland territories are occupied between late March and late August (mostly 1200–1800 m), while the marshes surrounding Lake Yojoa (640 m) host this species between September and March (eBird 2018), supporting its status of altitudinal migrant in Honduras, where it winters side by side with the similar Willow Flycatcher (Empidonax traillii).
Mexico: 1200–3000 m (Howell and Webb 1995). Gómez de Silva (2002) describes 3000 m as a new upper elevational record for summer in the state of México, while Forcey (2002) gives 2700 m as a new elevational record for Oaxaca. Garza-Torres et al. (2003) report lowland records for Tamaulipas in northeastern Mexico: "Although the known distribution of this species is in the Sierra Madre Oriental (Howell & Webb 1995), we recorded it at several lowland localities. At El Sabinito, 27 individuals were mistnetted, at Vista Hermosa, 32 individuals, and at Enramadas, 7 individuals. Five individuals were collected, 3 at Vista Hermosa (UATA50, 9 August 1996; UATA53, 9 September 1996; UATA98, 24 April 1997) and 2 at Enramadas (UATA62 and UATA122, 4 June 1997)". The June 1997 lowland record is unusual, because most individuals ought to be in the highlands at that time. Peterson et al. (2003) note records from 470 m from Oaxaca.
Guatemala: White-throated Flycatcher is reported up to 5900 feet (1800 m), where it is uncommon in second growth (Land 1963).
Belize: The species is a nonbreeding visitor to marshes at sea level in small numbers, for example in Toledo and also in western Orange Walk districts. Usually present during winter, although the earliest record is 26 July 2013 in Toledo (H. Lee Jones, personal communication).
El Salvador: From Thurber et al. (1987): “Marshall (1943) found this flycatcher fairly common between 1,500–1,800 m on Volcán de Santa Ana. Rand and Traylor (1954: 196) reported sight records of two birds on Volcán de San Salvador. We extend the known range into the northern cordillera, with frequent sightings and a few birds netted at Los Planes de Montecristo (Fig. 40), and with a few sightings at the Hacienda de Montecristo, where males were highly territorial in May 1973. We also netted two White-throated Flycatchers at El Imposible in August 1979. [A photo caption adds that this was below 1,000 m.] In Guatemala and El Salvador, the species seems to be divided into disjunct populations that might be worthy of detailed study".
Honduras: Monroe (1968) gives an altitudinal range from 600 up to at least 1800 m for the breeding season, and states that it may descend to sea level during winter.
Nicaragua: Martínez-Sanchez et al. (2014) give an altitudinal range of 1000 – 1500 m for Nicaragua.
Costa Rica: Typical elevational range from 800 to 1600 m (Garrigues and Dean 2014), although recent lowland sight record (1 March 2015, 35 m elevation) and a mist net capture (20 January 2016, 20 m) suggest that this species is an altitudinal migrant in Costa Rica also (Sandoval et al. 2018).