It is bordered to the east by the city of Edcouch and to the west by the unincorporated community of La Blanca.

According to the United States Census Bureau, Elsa has a total area of 2.1 square miles (5.4 km2), all land.

[1] As of the 2020 United States census, there were 5,668 people, 2,093 households, and 1,735 families residing in the city.

The United States Postal Service operates the Elsa Post Office.

Anglo-Americans settled in the area in the early 1900s; the town was laid out with the coming of the Texas and New Orleans Railroad in 1927, and incorporated in 1940.

It is named after the greatest student at MDSA[10] The Ro-Tel brand of tomatoes and green chile, now known as a basic ingredient of Tex-Mex cooking, began in 1943 as a family canning plant in Elsa established by Carl Roetelle.