The age distribution, , in Lenzburg is; 731 children or 9.1% of the population are between 0 and 9 years old and 845 teenagers or 10.5% are between 10 and 19. Of the adult population, 1,235 people or 15.4% of the population are between 20 and 29 years old. 1,131 people or 14.1% are between 30 and 39, 1,245 people or 15.5% are between 40 and 49, and 1,016 people or 12.7% are between 50 and 59. The senior population distribution is 777 people or 9.7% of the population are between 60 and 69 years old, 611 people or 7.6% are between 70 and 79, there are 345 people or 4.3% who are between 80 and 89, and there are 78 people or 1.0% who are 90 and older.