A 17-word Facebook reminder contributed to substantial increases in online voter registration, top election officials said.

At least nine secretaries of state have credited the social network’s voter registration reminder, displayed for four days in September, with boosting sign-ups, in some cases by considerable amounts. Data from nine other states show that registrations rose drastically on the first day of the campaign compared with the day before.

“Facebook clearly moved the needle in a significant way,” Alex Padilla, California’s secretary of state, said Tuesday.

In California, 123,279 people registered to vote or updated their registrations Sept. 23, the first day that Facebook users were presented with the reminder. That was the fourth-highest daily total in the history of the state’s online registration site.

Indiana similarly recorded its third-highest daily online registration total ever. Minnesota, meanwhile, broke its record for the most online voter registrations in a single week, thanks at least in part to the Facebook campaign, which continued through Sept. 26.

Those were among the nine states where election administrators extolled the social network in official statements. In nine others, online registration rose as Facebook began its effort, according to a review of data collected by the nonprofit Center for Election Innovation & Research. In those states, registration increased anywhere from two- to 23-fold on the first day the reminder went up, compared with the previous day.

Facebook’s effort is notable not just for boosting voter registration but also for the kinds of voters it may have helped to enlist. While Facebook could not provide demographic breakdowns of the users who registered, the social network is more popular among female internet users than male users, and the same is true for young users compared with older users, according to 2015 data from the Pew Research Center. Both groups — women and younger adults — tend to lean Democratic.

In California, for example, nearly 24 percent of online voter registrations during the Facebook campaign came from residents ages 17-25. Nearly 30 percent more came from Californians from 26 to 35 years old.

“It’s pretty clear that the Facebook reminder campaign disproportionately motivated young people to register,” Padilla said.

The reminder — “Are you registered to vote? Register now to make sure you have a voice in the election.” — was presented alongside two links: one leading to a federal directory of state voter registration websites; and another allowing users to share that they had registered. Only users who would be of voting age on Election Day saw the reminder, which appeared for both desktop and mobile users.

Officials greeted the effort enthusiastically.

“I applaud Facebook for joining our efforts to increase voter registration awareness,” Brian Kemp, Georgia’s secretary of state, said in a September statement, noting a substantial increase in traffic to the state’s voter registration website.

In Connecticut, 14,883 people registered to vote in the first three days of the Facebook campaign, a more than 12-fold increase over the same period a week earlier, the secretary of state said in a statement.

The secretaries of state in Colorado, Kentucky, Nebraska and West Virginia also credited Facebook, at least in part, for boosting registration.

While the reminder was part of an inaugural national campaign for the social network, it built on a tradition of promoting civic engagement for the company. As it has since 2008, Facebook plans to remind users to vote on Election Day.