San Isidro is a district of the Grecia canton, in the Alajuela province of Costa Rica.
It is named after Saint Isidore, a Catholic saint.
San Isidro has an area of km<sup>2</sup> and an elevation of metres. It is located on the slopes of Poás Volcano.
For the 2011 census, San Isidro had a population of inhabitants.
The district is covered by the following road routes: