Second District, formerly Poblacion, is a barangay in the municipality of Jalajala, in the province of Rizal. Its population as determined by the 2015 Census was 2,201. This represented 6.82% of the total population of Jalajala.

According to the 2015 Census, the age group with the highest population in Second District is 10 to 14, with 221 individuals. Conversely, the age group with the lowest population is 80 and over, with 18 individuals.

Combining age groups together, those aged 14 and below, consisting of the the young dependent population which include infants/babies, children and young adolescents/teenagers, make up an aggregate of 30.21% (665). Those aged 15 up to 64, roughly, the economically active population and actual or potential members of the work force, constitute a total of 64.56% (1,421). Finally, old dependent population consisting of the senior citizens, those aged 65 and over, total 5.22% (115) in all. 

The computed Age Dependency Ratios mean that among the population of Second District, there are 47 youth dependents to every 100 of the working age population; there are 8 aged/senior citizens to every 100 of the working population; and overall, there are 55 dependents (young and old-age) to every 100 of the working population. 

The median age of 26 indicates that half of the entire population of Second District are aged less than 26 and the other half are over the age of 26.

The population of Second District grew from 1,194 in 1990 to 2,201 in 2015, an increase of 1,007 people. The latest census figures in 2015 denote a positive growth rate of 2.81%, or an increase of 298 people, from the previous population of 1,903 in 2010.

Second District is situated at approximately 14.3499, 121.3303, in the island of Luzon. Elevation at these coordinates is estimated at 28.9 meters or 94.8 feet above mean sea level.