In metropolises like Seattle, it’s hard to imagine a day without internet. Urbanites are used to getting online for just about everything: work, shopping, entertainment, play, and communication. But 25 million Americans live without a broadband connection, according to the FCC. And 19 million of them live in rural areas.

Bridging that urban-rural internet divide has become a focus of some philanthropists and technology companies, like Microsoft. For the past year, the Redmond, Wash. software company has been working to deliver internet access to 2 million Americans through its Airband Initiative.

On Tuesday, Microsoft will announce plans to expand the program to an additional 1 million Americans by 2022. Microsoft President Brad Smith will announce the expansion of Airband at an event in Washington D.C. Tuesday.

Microsoft has partnered with internet service providers to deliver broadband to 13 states and 1 million Americans in Airband’s first year. Today’s announcement expands the program to a total of 25 states.

“While we’ve made significant progress, we know there’s a lot more to do to bring broadband to every American,” Smith said in a blog post announcing the expansion. “That’s why we are raising our ambition as a company and encourage the federal, state and local governments to do the same.”

To make Airband possible, Microsoft and internet providers rely on unused TV airwaves, also called white spaces.

Microsoft and partnering telecommunications companies are setting up revenue sharing arrangements to recoup the initial investments necessary to get these projects off the ground. Microsoft uses the proceeds to invest in additional Airband projects.

“Without a proper broadband connection, these communities can’t start or run a modern business, access telemedicine, take an online class, digitally transform their farm, or research a school project online,” Smith wrote, noting that federal statistics show high unemployment in areas without broadband access. “As a nation, we can’t afford to turn our backs on these communities as we head into the future.”