November 2014 polling by Cowen and Company found that 18-to-29-year-old US internet users were more likely than any other age group to use Instagram. Fully 44% of respondents who had used the social network in the past 30 days were in that age range.
Moving down the age spectrum, teens are also big fans of Instagram, as evidenced by an AVG study conducted in September 2014. Here, 62% of 11-to-16-year-old US internet users reported using Instagram—the second-highest percentage, trailing Facebook (80%) and well ahead of third-place Twitter (39%).
eMarketer estimates that there will be 60.3 million Instagram users in the US this year, and 12- to 34-year-olds will represent a whopping 78% of that total (18.2% share for teens, 27.6% for those 18 to 24 and 32.2% for adults 25 to 34). Fully 56.0% of 18-to-24-year-old US internet users will access Instagram via any device at least monthly in 2015, as will 45.5% of web users ages 12 to 17 and 47.5% of those 25 to 34. Read the rest at eMarketer.