Holbrook is located in Suffolk county New york with a geographic area of 6.9 square miles. The total population in Holbrook is 25,794 with 48.3% male and 51.7% female. Children under age 5 represent 5.7% of the population, under age 18 equal 22.6% of the population and over age 65 is 14.4% of the population. The median household income is $111,250, per capita income is $44,436. There are a total of 8,786 housing units with 78.3% owner occupied. Education includes 28.2% of residents that are high school graduates and 35.4% with a bachelor's degree or higher. The average temperature in Holbrook in the summer is 70 degrees, and in the winter 27 degrees.