El Semillero is a caserío (hamlet) in the Colonia Department of southwestern Uruguay.

The hamlet is located on Route 50, halfway between its junction with Route 1 and the small town of Tarariras.

Its distance by road from the capital of the department, Colonia del Sacramento, is about 24 kilometres (15 mi).

In 2011 El Semillero had a population of 600.

This article about a place in Colonia Department is a stub.