Yolillal is a district of the Upala canton, in the Alajuela province of Costa Rica.
The name means a place with an abundant yollillo, a plant.
Yolillal was created on 26 November 1980 by Decreto Ejecutivo 12092-G.
Yolillal has an area of km<sup>2</sup> and an elevation of metres.
For the 2011 census, Yolillal had a population of inhabitants.
The district is covered by the following road routes: