Senatorial district I covers all of the capital city of
San Juan, as well as
Aguas Buenas, and some regions of
Guaynabo. It has an approximate population of 462,035. In previous distributions, the territory covered by senatorial district I has changed. Originally, the district only covered the capital city of
San Juan. In the 1983 redistribution, the San Juan sector of
Sabana Llana was assigned to the
district of Carolina, but was reassigned to San Juan again in 1991. In the 2002 redistribution, some regions of
Guaynabo were assigned to the district, and in the most recent redistribution (2011), the municipality of
Aguas Buenas was also assigned to the district. ==Election results==