[7] In 1904, the Hidalgo and San Miguel Extension (now the Sam Fordyce Branch) of the St. Louis, Brownsville and Mexico Railway reached the Santa Anita Ranch.

John McAllen and his son James had donated land to the railroad to guarantee it would cross this area.

The new community, which was named for John McAllen, had the depot nearest the county seat, Hidalgo, 8 mi (13 km) to the south.

By 1911, 5,000 acres (2,000 ha) were under cultivation in East McAllen: commodity crops of cotton, alfalfa, broom corn, citrus fruits, grapes, and figs were raised.

In 1916, 20,000 New York state troops were stationed at McAllen to help quell border disturbances related to the Mexican Civil War.

In 1936, Hiram Garner opened the Valley Distillery, Incorporated, which produced wines from citrus juices.

The town was a petroleum and farm chemurgic center with a population of 11,877 in 1940, by which time it had adopted the nickname "The City of Palms".

Its construction resulted in increased tourist trade, making McAllen a winter resort and port of entry to Mexico.

The discovery of oil in the Reynosa area in 1947 attracted a large migration of people from the Mexican interior to jobs in the region.

The tourism industry continued to expand as people traveled to the area from both Mexico and the northern United States.

[12] Homeland Security Secretary Kirstjen Nielsen also visited the Border Patrol station in March 2019.

In order to deal with overcrowded facilities in 2019 resulting from the arrival of Central American migrant caravans, immigration authorities were releasing a few hundred asylum seekers daily to private groups that assist them with basic needs and travel arrangements.

[14] Portions of the razor wire coils considered unnecessary by the city were removed after troops had placed it at the border.

[15] The Marine Corps Commandant General Robert Neller expressed concerns about the impact of continuing border support on combat readiness for the troops.

The McAllen city limits extend to the southwest as far as the Rio Grande, directly north of Reynosa, Tamaulipas, in Mexico.

The Anzalduas International Bridge crosses the Rio Grande at this point, 11 mi (18 km) southwest of downtown McAllen.

According to the United States Census Bureau, the city has a total area of 48.6 square miles (126.0 km2), of which 0.3 sq mi (0.8 km2), or 0.62%, is covered by water.

Many thorny shrubs and deciduous trees occur in the area, such as the Rio Grande ash (Fraxinus berlandieriana), cedar elm (Ulmus crassifolia), and honey mesquite (Prosopis glandulosa).

[19] The warm season is extremely long, as average high temperatures from May through September are above 90 °F (32 °C) and average low temperatures are above 70 °F (21 °C), with relatively high dew point values, resulting in higher relative humidity and heat index values.

Winter temperatures in McAllen and surrounding Rio Grande Valley are some of the warmest in the contiguous United States outside of South Florida, and comparable to the Coachella and Imperial Valleys and Yuma Desert, but with warmer nighttime lows and higher dew points.

In December 2017, McAllen received almost 3 in (76 mm) of snow, nearly 13 years after the previous snowfall, which took place during the 2004 Christmas Eve United States winter storm.

In February 2021, McAllen reached record low temperatures between 10 °F (−12 °C) and 20 °F (−7 °C) and lost power, heat, and water for a week due to Winter Storm Uri.

The article noted that while the area has a higher prevalence of obesity and diabetes, its rates of infant mortality, HIV, and tobacco use were lower than the national average.

In the show, the overweight participant visits morbidly obese McAllen residents to find motivation for lifestyle and diet changes.

Also, an FTZ designation site is at the McAllen Miller International Airport to facilitate air cargo needs.

Under U.S. and Mexican laws and NAFTA provisions, the FTZ designation offers specific cost-saving opportunities to manufacturers.

Until 2014, McAllen was home to the Texas Thunder of the independent United League Baseball, who played at Edinburg Stadium.

The Quinta Mazatlan, a historic Spanish colonial mansion, is used as McAllen's wing of the World Birding Center.

This preserved green space offers visitors a chance to explore walking trails, climb a small hill, and has a cactus garden - all without any charge for admission.

The U.S. Customs and Border Protection (CBP) Rio Grande Valley Centralized Processing Center (CPC) is located at 3700 W Ursula Avenue, McAllen, Texas.