Facebook's app, by far, outranked any other in the US this year, according to ratings service Nielsen.
The social network's app reached the pinnacle with 126.7 million unique users on average each month from January through October, Nielsen said late last week. The figure was an 8 percent bump from 2014.
A far second was YouTube's app with an average of 97.6 million users each month over the same period. That was a 5 percent jump from last year for the video-streaming app.
Smartphones and tablets have become the go-to devices for our daily fix of texts, email, music, video and social networking. They're an integral part of how we work, commute and entertain. The top mobile apps reflect the diversity of those uses and activities.
Facebook also took the third spot with its Messenger app, which the company split off from its main app in 2014. The messaging app was the fastest-growing app this year in the US with a 31 percent increase in users over last year.
Google accounted for the next four spots, with its search app in fourth place, followed by Google Play, Google Maps and Gmail. Facebook-owned Instagram, a photo-sharing and social-networking app, was No. 8 with 55.4 million unique monthly users and 23 percent growth from the previous year.
Apple closed out the list with its Music app in ninth place, accounting for 54.6 million unique users each month, and its Maps app capturing 46.4 million users.
At first glance, the number for Apple Music seems especially high. In November, Apple CEO Tim Cook said that Apple Music had picked up 6.5 million people as paying members, with another 8.5 million people participating in the service's 90-day free trial. But Cook was referring to the Apple Music streaming service, which launched in June. The Apple Music app itself has been around for years as a vehicle for iPhone and iPad owners to play their own music.
Nielsen's data is based on a monthly survey of more than 30,000 mobile phone subscribers, 13 and older, in the US.