Weslaco is a city in Hidalgo County, Texas, United States. The population was 35,670 at the 2010 census. Weslaco derives its name from the W.E. Stewart Land Company. It was the hometown of Harlon Block, one of the Marines photographed raising the flag at Iwo Jima.
Streets north of the railroad tracks have Spanish names, and streets south of the railroad tracks have English ones as a consequence of a 1921 municipal ordinance which declared that land north of the tracks be reserved for Hispanic residences and businesses, and land south of the tracks be reserved for Anglo residences and businesses. During World War II, sandbag production reached a peak in Welaco, and the town declared itself the "sandbagging capital of the world."
Weslaco is part of the McAllen–Edinburg–Mission metropolitan area.