Weslaco is geographically located in the Gulf Coast hinterland - close to the floodplain in the lower Rio Grande valley, which is favorable for agriculture. The city is part of a series of towns and cities built along the US Highway 83 parallel to the Rio Grande and stretching from Mission to the Brownsville Regional Center in Cameron County, to the east. Located in the south-east corner of Hidalgo County, Weslaco is located in the area. The US Highway 83, which runs through the city center and passes north of the city center, is the most important connecting road. The climate in the region is subtropical and subhumid. The temperature data for the neighboring town of McAllen range from an average of 8° C in January to 35° C in July. The average annual temperature is 23° C. The average rainfall is 23 centimeters per month. The main rainy months are May and September. The population density in the city center corresponds to the city centers with between 4,900 and 6,100 inhabitants per square mile. It falls sharply towards the surrounding outlying districts. The population density there is between 1,300 and 2,500 inhabitants per square mile. In the Western and Eastern outer zones, it is significantly lower.

The first settlement of Europeans in today's urban area took place on the basis of land allocations granted by the New Panic authorities in the second half of the 18th century for the areas north of the lower Rio Grande. One of the first settlers was the pastoralist Juan José Ynojosa de Ballí. Ballí and its descendants managed their goods there until 1852. In 1904, the region was connected to the rail network of the St. Louis, Brownsville and Mexico Railway. In 1916, during the riots on the Mexican border following the Mexican Revolution, the US government stationed troops along the Rio Grande and built a control base between Mercedes and today's Weslaco.

Land ownership changed rapidly between 1910 and 1920. In 1913, two land sales companies secured a large part of the former Llano Grande land patent and started selling settlement plots. In December 1917 the W bought. E. Stewart Land Company has an area of about 121 square kilometers and sold this base area to several interested parties. The foundation of the city coincided with the construction of the Llano Grande military base - a training camp to train American recruits for World War I. Attracted by the view of the countryside and the resulting infrastructure, Anglo-American resettlers moved to Weslaco. Postservice was provided from the neighboring city of Mercedes until 1920. In 1920, the city had its own post office, a chamber of commerce, a bank, a building for the municipal administration, as well as electricity. In 1921, the Weslaco Independent School District was founded. The Texas Rangers also had their own station in the town.

Ethnically, a division into different urban areas took place at an early stage. A communal decree dating from 1921 assigned Hispanic business owners and residents to the north of the railway line, the Anglo-Saxon municipalities. As a result, the city developed into two different cities: "El pueblo americano", as the Anglo side of the city was called, consisted of well-built terraced houses, with paved roads and closed sewers. In "Mexican Town", however, certain corrugated iron huts, unpaved roads and outbuildings are the picture. Another regulation stipulated that Hispanic women were only allowed to shop on the city's Anglo side on Saturdays. The ethnic segregation also had consequences for the use of the Spanish language in public space: Roads north of the tracks, for example, had Spanish names, roads in "American Town" had English ones. Ethnic segregation has been exacerbated by groups like the Citizens Republican Committee, which called for the right to vote of Hispanics to be restricted or abolished altogether.

In the 1920s and 1930s, the town continued to prosper. In 1930 the population was around 4,800. The construction of a railway depot in 1927 moved to Weslaco for canning factories, a box mill and other production companies. In 1928, a ground-level water reservoir was built. Neon lighting was installed in the business district modernization in 1936. In 1939, the United States Farm Security Administration established a camp north of the city. North Weslaco, as it was named, was used to house migrant workers. In 1940, the city had about 180 local businesses and shops, a secondary school, a secondary school and a so-called Mexican and Negro school. In 1948, the A & I Citrus Centrum was opened - an agricultural experimental facility dedicated to grapefruit finishing. In 1954, an international bridge crossing the Rio Grande was put into operation south of the city.

In the 1960s and 1970s, Weslaco continued to be a major center of the citrus industry in the Rio Grande Valley. The population in 1960 was 15,649. Meanwhile, the city had nine schools, thirty churches, two banks, a hospital, a library, a newspaper, a radio station, and a television station. North Weslaco was renamed Northside Apartments in the 1990s. The town center is still surrounded by a series of loose settlements. Hispanics-inhabited Colonia housing estates (scattered throughout the Rio Grande Valley area and often precarious in terms of their home and sanitation) contrast with the Gated community complexes that are also found in the urban area and which, according to the municipal authorities, underscore the special quality of life in Weslaco.

In recent decades, Weslaco has been regularly affected by the hurricanes that regularly hit the region, including Hurricane Dolly (2008), which has affected a number of villages and towns in Hidalgo County.

According to United States Census Bureau data, Weslaco's population was 39,021 in 2016. 18,786 of them were male, 20,235 female. 26,455 inhabitants were 18 years or older, 12,566 children or young people, 6,297 over 65 years old. The median age was 33.3 years. 33,905 or 86.9% of respondents described themselves as Hispanic or Latino, 4,551 or 11.7% white, 394 or 1% Asian and 144 or 0.4% African-American. Finally, 42 0.1% said they belong to more than one ethnic group. According to Census, median income per household was $36,100 (USD). The median income obtained is significantly lower than the US total (USD 53,000) and the state of Texas (USD 51,900). People living in poverty accounted for 25% of the total, while those without health insurance accounted for 24.6%.

A famous citizen of the city is the U.S. Marines infantry Harlon Block. Block, a graduate of Weslaco High School, was one of the six US marines that hoisted the American flag on Iwojima Island on February 23, 1945. The action in which the block was involved was the second attempt explicitly launched for propaganda purposes. The recording led to the world-famous Pulitzer Prize awarded Photo Raising the Flag on Iwo Jima.

• Omar Figueroa (* 1989), Boxer