El Semillero is a caserío (hamlet) in the Colonia Department of southwestern Uruguay.
The hamlet is located on Route 50, half way 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.
Source: Instituto Nacional de Estadística de Uruguay