In Hidalgo County
, Weslaco is located just east of McAllen
along BR 83S near the Rio Grande
River and the United States/Mexico border.
Weslaco's population was 21,877 in 1992, by which time the city was part of the complex McAllen-Edinburg-Mission, Texas metropolitan area.
Weslaco is surrounded by many colonias, including Sun Country Estates, Expressway Heights, Sunrise, and Sunrise Hill. The estimated combined population of these four was 1,600 in 1986, when they consisted of about 355 dwellings.