Esenbeckia runyonii is a species of flowering tree in the citrus family, Rutaceae, that is native to northeastern Mexico,[2] with a small, disjunct population in the Lower Rio Grande Valley of Texas in the United States.

[9] The vast majority of E. runyonii trees occur in Nuevo León, Tamaulipas, San Luis Potosí and northwestern Hidalgo in northeastern Mexico.

[7] A few individuals[4] exist in the Tamaulipan mezquital along resacas in the Lower Rio Grande Valley of Texas in the United States.

It is possible that this disjunct population arose from seeds dispersed by flooding of the Rio Grande's drainage basin in the Sierra Madre Oriental.

[7] Post-sized branch cuttings from Limoncillo are planted in the ground during the dry season by farmers in Mexico.